阅读说明：本技术 一种芯片工作状态选择电路、方法及其应用 (Chip working state selection circuit, method and application thereof ) 是由 赵汗青 冯奕翔 于 2018-07-10 设计创作，主要内容包括：一种芯片工作状态选择电路、方法及其应用,包括第一电阻RV、第二电阻RF和阻值处理电路,所述的阻值处理电路封装在芯片U1中,所述的第一电阻RV和第二电阻RF分别通过芯片U1的两个管脚与阻值处理电路相连,阻值处理电路将采集到的阻值信号相比得到表征第一电阻RV与第二电阻RF阻值比的比例信号VD,通过调整第一电阻RV与第二电阻RF的阻值比,使得芯片U1中的功能电路根据与阻值比对应的比例信号VD调整芯片U1的工作状态。本发明提供一种可实现多种工作状态调整、电路结构简单可靠、控制管脚占用少的芯片工作状态选择电路、方法及其应用。(A chip working state selection circuit, a method and application thereof are disclosed, the chip working state selection circuit comprises a first resistor RV, a second resistor RF and a resistance value processing circuit, the resistance value processing circuit is packaged in a chip U1, the first resistor RV and the second resistor RF are respectively connected with the resistance value processing circuit through two pins of a chip U1, the resistance value processing circuit compares collected resistance value signals to obtain a proportional signal VD representing the resistance value ratio of the first resistor RV to the second resistor RF, and a functional circuit in the chip U1 adjusts the working state of the chip U1 according to the proportional signal VD corresponding to the resistance value ratio by adjusting the resistance value ratio of the first resistor RV to the second resistor RF. The invention provides a chip working state selection circuit, a method and application thereof, which can realize adjustment of various working states, have simple and reliable circuit structure and small occupied control pins.)

1. The chip working state selection circuit is characterized by comprising a first resistor RV, a second resistor RF and a resistance value processing circuit (1), wherein the resistance value processing circuit (1) is packaged in a chip U1, and the first resistor RV and the second resistor RF are respectively connected with the resistance value processing circuit (1) through two pins of a chip U1;

the resistance processing circuit (1) compares the collected resistance signals to obtain a proportional signal VD representing the resistance ratio of the first resistor RV to the second resistor RF, and adjusts the resistance ratio of the first resistor RV to the second resistor RF so that the functional circuit in the chip U1 adjusts the working state of the chip U1 according to the proportional signal VD corresponding to the resistance ratio.

2. The chip operation state selection circuit according to claim 1, wherein the pins of the chip U1 include a control pin a connected to the adjustable first resistor RV for providing a resistance value of a variable portion of the resistance ratio and a functional pin B configured to be connected to the fixed second resistor RF for providing a resistance value of a fixed portion of the resistance ratio.

3. The chip operation state selection circuit according to claim 2, wherein the functional pin B is further connected to a utilization circuit (3) and a resistance value processing circuit (1) packaged in the chip U1, respectively, and the second resistor RF is used as an external resistor outside the chip U1 of the utilization circuit (3).

4. The chip operation state selection circuit according to claim 1, wherein the proportional signal VD outputted from the resistance value processing circuit (1) is a digital signal.

5. The chip operating condition selection circuit according to claim 1, wherein the resistance value processing circuit (1) comprises a current source and an analog-to-digital converter ADC, one end of the first resistor RV is connected to the current source and the other end is grounded, a first sampling point O is provided between the first resistor RV and the current source, one end of the second resistor RF is connected to the current source and the other end is grounded, and a second sampling point P is provided between the second resistor RF and the current source;

the first sampling point O and the second sampling point P are respectively connected to an input end of an analog-to-digital converter ADC, and the analog-to-digital converter ADC is configured to compare the first resistor RV with the second resistor RF and perform analog-to-digital conversion on a comparison result to obtain a proportional signal VD.

6. The chip operation state selection circuit according to claim 5, wherein a sampling switch is disposed between the first sampling point O and the current source, and a sampling switch is disposed between the second sampling point P and the current source, the sampling switch is configured to be turned on when the chip U1 is powered on, so as to obtain a proportional signal VD representing a ratio of the first resistance RV to the second resistance RF at the powered-on time.

7. The chip operating state selection circuit according to claim 1, wherein the output of the resistance value processing circuit (1) is connected to the control input of the functional circuit, the proportional signal VD can be directly input to the corresponding functional circuit, and the functional circuit adjusts the operating state of the chip U1 according to the proportional signal VD corresponding to the resistance value ratio;

or the chip further comprises a state control circuit (2), the output of the resistance value processing circuit (1) is connected with the input of the state control circuit (2), the proportional signal VD is input into the state control circuit (2), and the state control circuit (2) controls the corresponding functional circuit according to the proportional signal VD corresponding to the resistance value ratio, so that the adjustment of the working state of the chip U1 is completed.

8. The chip operation state selection circuit according to any one of claims 1 to 7, wherein the first resistor RV and the second resistor RF are in the form of two independent resistors or the first resistor RV and the second resistor RF respectively represent equivalent resistors connected to two pins of a chip U1.

9. The chip operation state selection circuit according to any one of claims 1 to 7, wherein the functional circuit in the chip U1 adjusts the operation state of the chip U1 according to the proportional signal VD corresponding to the resistance ratio, including adjusting the operation mode of the chip, adjusting the operation parameters of the chip, and selecting the function.

10. The application of the chip working state selection circuit is characterized in that the chip working state selection circuit is applied to an LED driving chip (100), a feedback detection circuit, a pulse width modulator and a transistor are packaged in the LED driving chip (100), and pins of the LED driving chip (100) comprise a voltage feedback pin DSEN and a high-voltage power supply input pin DRAIN;

the chip working state selection circuit comprises a first resistor RV, a second resistor RF and a resistance value processing circuit (1), wherein the resistance value processing circuit (1) is packaged in a chip U1;

the pin of the LED driving chip (100) further comprises a control pin A, the control pin A is connected with a first resistor RV arranged outside the chip, a voltage feedback pin DSEN is connected with a second resistor RF arranged outside the chip, the control pin A and the voltage feedback pin DSEN are respectively connected with the input of a resistance value processing circuit (1), the output of the resistance value processing circuit (1) is connected with a pulse width modulator, the resistance value ratio of the first resistor RV and the second resistor RF is adjusted according to the maximum value of the switch opening time to be adjusted, the resistance value processing circuit (1) converts the resistance value ratio into a proportional signal VD and inputs the proportional signal VD to the pulse width modulator, and then the adjustment of the maximum value of the switch opening time is completed.

11. The application of the chip operation state selection circuit according to claim 10, wherein the resistor RF is a constant value resistor, the second resistor RF is a voltage sampling resistor of the feedback detection circuit, and the resistance of the first resistor RV is adjusted according to the maximum value of the switch on-time to be adjusted, thereby adjusting the resistance ratio of the first resistor RV to the second resistor RF.

12. The application of the chip operation state selection circuit according to claim 10, wherein the first resistor RV and the second resistor RF represent equivalent resistors, respectively, and the second resistor RF is an equivalent resistor formed by connecting at least two resistors in parallel.

13. A chip working state selection method is characterized in that resistance value signals representing resistance values of a first resistor RV and a second resistor RF are collected respectively, a proportional signal VD representing the resistance value ratio of the first resistor RV and the second resistor RF is obtained by comparing the collected resistance value signals, and the proportional signal VD is input into a functional circuit in a chip U1 to be used for controlling the working state of a chip U1.

14. The chip operation state selection method according to claim 13, wherein the separately collecting the resistance signals representing the resistance values of the first resistor RV and the second resistor RF comprises separately collecting the resistance signals representing the resistance values of the first resistor RV and the second resistor RF at a power-on time of the chip U1.

15. The chip operation state selection method of claim 13, wherein the proportional signal VD is a digital signal, and the proportional signal VD is inputted to a functional circuit in the chip U1 for controlling the operation state of the chip U1, including adjusting the operation mode of the chip, adjusting the operation parameters of the chip, and selecting the function.

Technical Field

The invention relates to the field of integrated circuit design, in particular to a chip working state selection circuit, a chip working state selection method and application of the chip working state selection method.

Background

As integrated circuit technology advances, chips are being developed in a direction of more compact size and more complex functions. In the process of the chip in the actual circuit application, in order to improve the working efficiency of the chip, the selective operations such as switching the working mode of the chip and adjusting the working parameters in the chip can be realized through partial pins on the chip. Specifically, in the prior art, the operation of selecting the working state of the chip is generally accomplished by applying high and low levels to the control pin of the chip or detecting the closing time of the external switch of the chip through an internal circuit in the chip.

Adopt high, the technical scheme of low level adjustment chip operating condition is only two kinds of circumstances owing to the voltage of applying the pin, the operating condition that leads to can control the selection is also only limited to two kinds, the state selection that has restricted the chip and then greatly reduced the work efficiency of chip, if want to enlarge selection state scope through high, the mode of low level and can only increase the control pin, under the more and more compact and more precious condition of pin effect of chip size, the waste of pin can certainly be caused in this kind of design, the availability factor of chip has been reduced. And the technical scheme that the selection operation is completed by detecting the closing time of the switch has the advantages that a detection circuit built in the chip is complex, the packaging size of the chip can be influenced, the design difficulty and the cost of the chip are increased, in addition, the scheme of the peripheral switch cannot be applied to all types of chips, and the practicability is low.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a chip working state selection circuit, a chip working state selection method and a chip working state selection application, wherein the chip working state selection circuit can realize adjustment of multiple working states, is simple and reliable in circuit structure and occupies less control pins.

In order to achieve the purpose, the invention adopts the following technical scheme:

a chip working state selection circuit comprises a first resistor RV, a second resistor RF and a resistance value processing circuit 1, wherein the resistance value processing circuit 1 is packaged in a chip U1, and the first resistor RV and the second resistor RF are connected with the resistance value processing circuit 1 through two pins of a chip U1 respectively. The resistance processing circuit 1 compares the collected resistance signals to obtain a proportional signal VD representing the resistance ratio of the first resistor RV to the second resistor RF, and adjusts the resistance ratio of the first resistor RV to the second resistor RF, so that the functional circuit in the chip U1 adjusts the working state of the chip U1 according to the proportional signal VD corresponding to the resistance ratio.

Preferably, the pins of the chip U1 include a control pin a connected to the adjustable first resistor RV for providing the resistance of the variable portion of the resistance ratio, and a functional pin B configured to be connected to the fixed second resistor RF for providing the resistance of the fixed portion of the resistance ratio.

The functional pin B is preferably connected to the utilization circuit 3 and the resistance value processing circuit 1 packaged in the chip U1, respectively, and the second resistor RF is used as an external resistor outside the chip U1 of the utilization circuit 3.

Preferably, the proportional signal VD output by the resistance value processing circuit 1 is a digital signal.

Preferably, the resistance processing circuit 1 includes a current source and an analog-to-digital converter ADC, one end of the first resistor RV is connected to the current source, and the other end is grounded, a first sampling point O is provided between the first resistor RV and the current source, one end of the second resistor RF is connected to the current source, and the other end is grounded, and a second sampling point P is provided between the second resistor RF and the current source. The first sampling point O and the second sampling point P are respectively connected to an input end of an analog-to-digital converter ADC, and the analog-to-digital converter ADC is configured to compare the first resistor RV with the second resistor RF and perform analog-to-digital conversion on a comparison result to obtain a proportional signal VD.

Preferably, a sampling switch is arranged between the first sampling point O and the current source, a sampling switch is also arranged between the second sampling point P and the current source, and the sampling switch is configured to be turned on when the chip U1 is powered on, so as to obtain a proportional signal VD representing a ratio of the first resistor RV to the second resistor RF at the power-on time.

Preferably, the output of the resistance value processing circuit 1 is connected to the control input of the functional circuit, the proportional signal VD may be directly input to the corresponding functional circuit, and the functional circuit adjusts the operating state of the chip U1 according to the proportional signal VD corresponding to the resistance value ratio. Or the state control circuit 2 is further included, the output of the resistance value processing circuit 1 is connected with the input of the state control circuit 2, the proportional signal VD is input into the state control circuit 2, and the state control circuit 2 controls the corresponding functional circuit according to the proportional signal VD corresponding to the resistance value ratio, so that the adjustment of the working state of the chip U1 is completed.

Preferably, the first resistor RV and the second resistor RF are in the form of two independent resistors or the first resistor RV and the second resistor RF respectively represent equivalent resistors connected to two pins of the chip U1.

Preferably, the functional circuit in the chip U1 adjusts the operating state of the chip U1 according to the proportional signal VD corresponding to the resistance ratio, including adjusting the operating mode of the chip, adjusting the operating parameters of the chip, and selecting the function.

The method further comprises the application of a chip working state selection circuit, wherein the chip working state selection circuit is applied to the LED driving chip 100, a feedback detection circuit, a pulse width modulator and a transistor are packaged in the LED driving chip 100, and pins of the LED driving chip 100 comprise a voltage feedback pin DSEN and a high-voltage power supply input pin DRAIN. The chip working state selection circuit comprises a first resistor RV, a second resistor RF and a resistance value processing circuit 1, wherein the resistance value processing circuit 1 is packaged in a chip U1. The pins of the LED driving chip 100 further include a control pin a, the control pin a is connected to a first resistor RV external to the chip, the voltage feedback pin DSEN is connected to a second resistor RF external to the chip, the control pin a and the voltage feedback pin DSEN are respectively connected to an input of the resistance processing circuit 1, an output of the resistance processing circuit 1 is connected to the pulse width modulator, a resistance ratio of the first resistor RV to the second resistor RF is adjusted according to a maximum value of a switch on time to be adjusted, and the resistance processing circuit 1 converts the resistance ratio into a proportional signal VD to be input to the pulse width modulator, thereby completing adjustment of the maximum value of the switch on time.

The invention also comprises a chip working state selection method, which is used for respectively acquiring resistance value signals representing the resistance values of the first resistor RV and the second resistor RF, comparing the acquired resistance value signals to obtain a proportional signal VD representing the resistance value ratio of the first resistor RV and the second resistor RF, and inputting the proportional signal VD into a functional circuit in the chip U1 to control the working state of the chip U1.

According to the chip working state selection circuit, the chip working state selection method and the application of the chip working state selection circuit, the working state of the chip is adjusted by the functional circuit in the chip according to the proportional signal corresponding to the resistance ratio by detecting the resistance ratio of the first resistor and the second resistor, the adjustment operation of various working states of the chip is completed by the chip under the condition of utilizing few pins, the circuit structure is simple, and the control is accurate. In addition, the resistance value of the chip external resistor is less interfered by external factors such as temperature and the like, and is relatively stable, so that the stability of adjusting the working state of the chip is improved.

Drawings

FIG. 1 is a schematic diagram of a prior art chip operating state selection scheme;

FIG. 2 is a schematic diagram of the chip operation state selection circuit according to the present invention;

FIG. 3 is a circuit diagram of an embodiment of a chip operating state selection circuit of the present invention;

FIG. 4 is a block diagram of an embodiment of the chip operation state selection circuit according to the present invention;

fig. 5 is a flowchart of a chip operation state selection method of the present invention.

Detailed Description

In order to make the technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention are further described in detail below with reference to the accompanying drawings and the embodiments.

Fig. 1 is a schematic diagram illustrating the operation of switching the operating state of a chip according to the prior art by inputting a switching signal through a pin, and the exemplary chip U0 in fig. 1 has eight pins, which include at least one control pin configured to input a switching signal, such as a high-level signal, a low-level signal, a switching signal, a regulated voltage signal, and the like. The switching of the working state of the chip can comprise switching of a working mode, adjustment of chip parameters and the like. Specifically, the example chip U0 includes a first control pin CON1, the first control pin CON1 is configured to input a first switching signal SWITCH1, SWITCH the example chip U0 to a normal operation mode or adjust a parameter of the example chip U0 to a first threshold when the first switching signal SWITCH1 is a high-level signal, and SWITCH the example chip U0 to a test operation mode or adjust a parameter of the example chip U0 to a second threshold when the first switching signal SWITCH1 is a low-level signal. As can be seen from the above analysis, the case that the switching signal is at high and low levels can only realize that the exemplary chip U0 switches in two operating modes or can only select two parameter thresholds for adjustment, and if a switching adjustment scheme is to be added, only the number of the control pins can be increased, for example, if a switching of four operating modes or four parameter thresholds is to be added in fig. 1, the first control pin CON1 and the second control pin CON2 are required to be matched together, but this will inevitably cause waste of pin resources and complex logic for matching multiple pins, thereby increasing difficulty in designing circuits in the chip. When the first switching signal SWITCH1 is a switching signal, circuit structures such as a timing circuit need to be added to the example chip U0 to increase the difficulty of chip design and packaging, and this scheme requires an external switching element and cannot be applied to a high-voltage input chip, so that the flexibility of chip application and design is poor and the practicability is low. In addition, when the first switching signal SWITCH1 is a regulated voltage signal, the circuit structure requiring high accuracy for sampling voltage in the chip is complex, which increases the design difficulty, and once the voltage switching signal is detected inaccurately, the switching misoperation is caused, which affects the chip stability.

The invention aims to overcome the defects of the prior art and provides a chip working state selection circuit, a chip working state selection method and a chip working state selection application, wherein the chip working state selection circuit can realize adjustment of various working states, is simple and reliable in circuit structure and occupies less control pins. Fig. 2 is a schematic structural diagram of the chip operation state selection circuit according to the present invention. The chip working state selection circuit comprises a first resistor RV, a second resistor RF and a resistance value processing circuit 1, wherein the resistance value processing circuit 1 is packaged in a chip U1, the first resistor RV and the second resistor RF are respectively connected with the resistance value processing circuit 1 through two pins of a chip U1, the resistance value processing circuit 1 is used for collecting and processing resistance value signals representing the resistance values of the first resistor RV and the second resistor RF, the resistance value processing circuit 1 compares the collected resistance value signals to obtain a proportional signal VD representing the resistance value ratio of the first resistor RV to the second resistor RF, the proportional signal VD is used for controlling the working state of the chip U1, and the resistance value ratio of the first resistor RV to the second resistor RF is adjusted through matching the resistance values, so that a functional circuit in the chip U1 adjusts the working state of the chip U1 according to the proportional signal VD corresponding to the resistance value ratio. Preferably, the proportional signal VD output by the resistance value processing circuit 1 is a digital signal. The first resistor RV and the second resistor RF are in the form of two independent resistors or the first resistor RV and the second resistor RF represent equivalent resistors connected to two pins of the chip U1, respectively. The chip working state selection circuit of the invention is based on different resistance ratiosThe value control working state can realize the adjustment operation of various working states of the chip under the condition of utilizing few pins, and the circuit has simple structure and accurate control. Furthermore, the resistance value processing circuit converts the resistance ratio analog signal into a digital signal, so that different resistance values have relatively unique digital signals corresponding to the digital signals, the possibility of misoperation is reduced, the control accuracy is improved, and theoretically, 2 corresponding to different resistance values can be determined according to the digit and the resistance accuracy of the analog-to-digital converterⁿThe number of controllable operating states is greatly increased by the number of operating states (n represents the number of bits of the analog-to-digital converter). In addition, the resistance value of the chip external resistor is less interfered by external factors such as temperature and the like, and is relatively stable, so that the stability of adjusting the working state of the chip is improved.

The chip operation state selection circuit in fig. 2 further includes a state control circuit 2. When the proportional signal VD controls the working state of the adjusting chip U1, the output of the resistance value processing circuit 1 is connected with the control input of the functional circuit, the proportional signal VD can be directly input to the corresponding functional circuit, and the functional circuit adjusts the working state of the chip U1 according to the proportional signal VD corresponding to the resistance value ratio. The output of the resistance value processing circuit 1 can be connected with the input of the state control circuit 2, the proportional signal VD is input into the state control circuit 2, and the state control circuit 2 controls the corresponding functional circuit according to the proportional signal VD corresponding to the resistance value ratio, so as to complete the adjustment of the working state of the chip U1. The use method of the proportional signal VD is flexible, the functional circuit can be directly controlled to improve the working efficiency, and the proportional signal VD can be used for carrying out unified control management on the functional circuit through the intermediate link of the state control circuit 2, so that the accurate adjustment of the working state of the chip is realized.

It should be noted that, what is shown in fig. 2 is only a schematic diagram of the framework of the chip U1 of the present invention, the chip U1 may be any one of various types of chips (such as an LED driving chip), and the operating state of the control chip includes adjusting the operating mode of the chip, adjusting the operating parameters of the chip, selecting functions, and the like. The chip U1 not only has the resistance processing circuit 1 and the state control circuit 2, but also includes a plurality of functional circuits, the proportional signal VD can directly control the functional circuit in the chip U1 or the state control circuit 2 can control the corresponding functional circuit in the chip U1 according to different proportional signals VD so as to change the working state of the chip U1. Two pins of the chip U1 are connected with a first resistor RV and a second resistor RF respectively, and other pins of the chip U1 can be connected with external electronic elements to form a system circuit according to the actual function of the chip. The first resistor RV and the second resistor RF are not limited to two independent resistors, and the first resistor RV and the second resistor RF may also represent equivalent resistors connected to two pins of the chip U1, that is, the first resistor RV and/or the second resistor RF may be equivalent resistors connected in series, parallel, or in a mixed manner with at least two resistors, respectively, and then the proportional signal VD is a result of comparing the equivalent resistors. Likewise, the pins of chip U1 in FIG. 2 are not limited to eight, depending on the particular chip type. The resistance ratio is not limited to the first resistance RV compared to the second resistance RF, and may be obtained by comparing the second resistance RF to the first resistance RV.

The method for adjusting the resistance can be various, the corresponding relation between the resistance ratio and the working state can be determined before the chip is applied, and the design and the construction of the chip application circuit are completed according to the required working state of the chip and the corresponding relation matched with the resistance with the corresponding resistance. And when the circuit is designed and built, the fixed-value resistor and the variable resistor can be selected according to the corresponding relation, and the variable resistor has the advantage that the working mode can be flexibly selected under the condition that the resistor in the circuit is not required to be replaced. Preferably, a sampling switch is arranged in the resistance value processing circuit 1, the working state is determined at the power-on time of the chip, the chip completes the detection of the resistance value ratio through the resistance value processing circuit 1 at the power-on time, and other functions are continuously operated after the working state is determined. When the working state is judged according to the resistance ratio, the corresponding working state can be determined according to the specific resistance ratio, for example, the proportional signal VD output by the resistance processing circuit 1 is a digital signal, and if the number of bits of the analog-to-digital converter in the resistance processing circuit 1 is three, the digital signal output by the analog-to-digital converter has 2³(8) cases, each case representing a correspondence of the resistance ratio to an operating state; or according to the resistance valueFor example, the chip working state selection circuit can be applied to an LED driving chip and used for adjusting the duty ratio time parameter in the LED driving chip, the maximum value limitation of Ton is adjusted by adjusting the resistance value ratio range, the working range of the LED driving chip is limited, namely when the input voltage is low to a certain value to enable Ton to reach the maximum value, the input voltage continues to drop, and the output current begins to drop. The correspondence relationship between the specific resistance ratio range and the operating state is shown in table 1 below.

TABLE 1 example of the relationship between the resistance ratio and the operating condition of the ADC for three bits

Serial number	Proportional signal VD	Range of resistance ratio	Working state (Unit: mus)
				1	000	r<1.5	Ton_max＝4.2
2	001	1.5<r<2.5	Ton_max＝4.7
				3	010	2.5<r<3.5	Ton_max＝5.3
4	011	3.5<r<4.5	Ton_max＝6
				5	100	4.5<r<5.5	Ton_max＝6.9
6	101	5.5<r<6.5	Ton_max＝8.3
				7	110	6.5<r<7.5	Ton_max＝10.4
8	111	7.5<r	Ton_max＝20

In table 1, r is the resistance ratio and Ton _ max is the maximum value of the switch on time.

In order to further optimize the resource utilization of the chip pins. Specifically, the resistance of the first resistor RV in fig. 2 can be adjusted, and the resistance of the second resistor RF is fixed. The resistance ratio is changed by adjusting the resistance of the first resistor RV according to the required working state, so that the resistance processing circuit 1 outputs a corresponding proportional signal VD according to different resistance ratios, and the working state of the control chip U1 is realized. Preferably, the pins of the chip U1 include a control pin a connected to an adjustable first resistor RV for providing the resistance of the variable part of the resistance ratio, and a functional pin B configured to be connected to a fixed second resistor RF for providing the resistance of the fixed part of the resistance ratio, and the functional pin B is further connected to the utilization circuit 3 and the resistance processing circuit 1 packaged in the chip U1, respectively, and the second resistor RF also serves as an external resistor outside the chip U1 of the utilization circuit 3. For example, the usage circuit 3 is a feedback detection circuit, the functional pin B is a voltage feedback pin DSEN of the chip, the second resistor RF is an external resistor of the feedback pin DSEN for voltage sampling, the functional pin B (i.e., the voltage feedback pin DSEN) can be connected to the load output terminal or the auxiliary winding through a resistor divider (i.e., the second resistor RF) to reflect the output voltage, and meanwhile, the resistance comparator 1 further collects the resistance of the second resistor RF through the functional pin B, because the first function of the functional pin B is also to implement the corresponding function of the usage circuit 3, the second resistor RF is required to be a fixed resistor to complete the corresponding function of the usage circuit 3, and then the adjustment of the resistance ratio can be completed only by adjusting the resistance of the first resistor RV. In particular, in order not to affect the normal operation of the functional pin B corresponding to the using circuit 3, it may be configured that the operating state is determined by detecting the resistance ratio when the chip is powered on, and then the corresponding operation of the using circuit 3 is executed. In addition, the first resistor RV and the second resistor RF are not limited to two independent resistors, and the first resistor RV and the second resistor RF may also represent equivalent resistors connected to two pins of the chip U1, respectively. It should be noted that the circuit used may be the same as or different from the functional circuit controlled by the proportional signal VD in the chip. The scheme of setting the resistor as a fixed resistor and a variable resistor simplifies the mode of adjusting the resistance ratio, reduces the difficulty of selecting circuit design and improves the efficiency of practical application. Furthermore, the fixed value resistor connected with the pins with actual functions is used as a fixed part in the resistance ratio, so that the adjustment mode of the resistance ratio is simplified, more importantly, the resource utilization rate of the chip pins is optimized, the function pins are multiplexed, the selection of the working state of the chip can be realized only through one control pin, the use efficiency of the functions of the chip pins is improved, and the design structure of the chip application circuit is simple and reliable.

Fig. 3 is a circuit diagram of a specific embodiment of the chip operating state selection circuit of the present invention, and a dashed line frame in fig. 3 is a circuit diagram of a specific embodiment of the resistance value processing circuit 1, where the resistance value processing circuit 1 is packaged in a chip U1 and includes a current source and an analog-to-digital converter ADC, the first resistor RV and the second resistor RF are external resistors of the chip U1, the first resistor RV and the second resistor RF are respectively connected to two pins of the chip U1, one end of the first resistor RV is connected to the current source of the resistance value processing circuit 1, and the other end is grounded, a first sampling point O is disposed between the first resistor RV and the current source, one end of the second resistor RF is connected to the current source of the resistance value processing circuit 1, and the other end is grounded, a second sampling point P is disposed between the second resistor RF and the current source, and the first sampling point O and the second sampling point P are respectively connected to an input end of the analog-to-, the first sampling point O and the second sampling point P are respectively configured to input a first voltage signal representing the resistance value of the first resistor RV and a second voltage signal representing the resistance value of the second resistor RF to the analog-to-digital converter ADC, and the analog-to-digital converter ADC is configured to compare the first resistor RV with the second resistor RF and perform analog-to-digital conversion on a comparison result to obtain a proportional signal VD. Preferably, the first resistor RV is adjustable in resistance and connected to the control pin a, and the second resistor RF is fixed in resistance and connected to the function pin B. The resistance ratio is changed by adjusting the resistance of the first resistor RV, so that the resistance processing circuit 1 outputs corresponding proportional signals VD according to different resistance ratios, and the working state of the control chip U1 is realized. And, be equipped with the sampling switch between first sampling point O and the current source, also be equipped with the sampling switch between second sampling point P and the current source, the sampling switch is configured to switch on when chip U1 is electrified, and then obtains the proportional signal VD who characterizes first resistance RV and second resistance RF ratio at the time of the power-on, set up the control that the sampling switch realized sampling the resistance value, because second circuit RF can regard as the peripheral hardware definite value resistance or the equivalent resistor of specific use circuit, set up the sampling switch and avoided influencing the normal work of specific use circuit in the resistance sampling process, guarantee the stability of circuit and application system work. Specifically, the proportional signal VD obtained by the analog-to-digital converter ADC can be directly input to the corresponding functional circuit, and the functional circuit adjusts the operating state of the chip U1 according to the proportional signal VD corresponding to the resistance ratio. The proportional signal VD obtained by the analog-to-digital converter ADC can also be input into the state control circuit 2, and the state control circuit 2 controls the corresponding functional circuit according to the proportional signal VD corresponding to the resistance value ratio, thereby completing the adjustment of the working state of the chip U1. In addition, the embodiment of the resistance value processing circuit 1 is not limited to the above-described embodiment, and any circuit that can compare the resistance values of the first resistor RV and the second resistor RF and convert the values into digital signals may be used as the resistance value processing circuit. The resistance processing circuit has a simple structure, reduces the difficulty of circuit design, facilitates the packaging processing of chips and improves the practicability.

Fig. 4 is a block diagram of an embodiment of the selection circuit according to the present invention. The chip operating state selecting circuit in fig. 4 is applied to an LED driving chip 100, the LED driving chip 100 in fig. 4 is a common LED constant current driving chip structure, and a supply voltage and VDD voltage detecting circuit, a high voltage power supply circuit, a feedback detecting circuit, a pulse width modulator, a temperature compensating circuit, a transistor, an amplifier, and the like are packaged in the LED driving chip 100. The feedback detection circuit detects the load voltage condition and adjusts the transistor through the pulse width modulator, so that the output voltage is constant. The pins of the LED driving chip 100 in fig. 4 include a voltage feedback pin DSEN, a power supply pin VDD, a current detection pin CS, a high-voltage power supply input pin DRAIN, and the like. The working state selection circuit of the invention can be applied to the LED driving chip 100 in fig. 4, specifically, the LED driving chip 100 is further packaged with a resistance value processing circuit 1, the pin of the LED driving chip 100 further includes a control pin a, the control pin a is connected to a first resistor RV external to the chip, a voltage feedback pin DSEN of the LED driving chip 100 is connected to a second resistor RF external to the chip, the control pin a and the voltage feedback pin DSEN are respectively connected to an input of the resistance value processing circuit 1, and the second resistor RF is a fixed value resistor, the second resistor RF is also used as a voltage sampling resistor of a feedback detection circuit (i.e. a using circuit) packaged in the LED driving chip 100, an output of the resistance value processing circuit 1 is connected to a pulse width modulator (i.e. a functional circuit) packaged in the LED driving chip 100, the maximum value of the switching on time to be adjusted is used to adjust the first resistor RV, and further adjusting the resistance ratio of the first resistor RV and the second resistor RF, converting the resistance ratio into a proportional signal VD by the resistance processing circuit 1, and inputting the proportional signal VD to the pulse width modulator to complete the adjustment of the maximum value of the switch on time. It should be noted that the adjustment of the resistance ratio is not limited to the adjustment of the maximum value of the on-time in the working state of the chip, and may also be used to adjust parameters in other functional circuits, such as adjusting the temperature parameter value in the temperature compensation circuit, and may also implement the switching of the working mode of the chip, for example, implementing the switching of the chip between the working mode and the test mode by adjusting the resistance ratio. The proportional signal VD output by the resistance value processing circuit 1 may be directly input to the corresponding functional circuit, or may be input to the state control circuit 2, and then the state control circuit 2 controls the functional circuits in a unified manner. In particular, the corresponding function circuit or state control circuit 2 is not limited to perform corresponding adjustment according to the proportional signal VD representing one resistance ratio, but may perform corresponding adjustment according to at least two proportional signals VD representing ranges of resistance ratios. As can be seen from the specific application of fig. 4, only one control pin a is needed on the chip to complete adjustment and switching of multiple working states, the circuit building and design process is simple and reliable, and the selection circuit has a simple structure and is easy to package. In addition, the adjusting mode according to the proportional signal is flexible, and the efficiency is improved.

The invention also includes a chip working state selection method, as shown in fig. 5, the method includes respectively collecting resistance signals representing the resistance values of the first resistor RV and the second resistor RF, comparing the collected resistance signals to obtain a proportional signal VD representing the resistance ratio of the first resistor RV to the second resistor RF, and inputting the proportional signal VD into a functional circuit in the chip U1 for controlling the working state of the chip U1. Preferably, the collecting the resistance signals representing the resistance values of the first resistor RV and the second resistor RF respectively includes collecting the resistance signals representing the resistance values of the first resistor RV and the second resistor RF respectively at the power-on time of the chip U1. In addition, the proportional signal VD is a digital signal, and the functional circuit that inputs the proportional signal VD into the chip U1 is used to control the operating state of the chip U1, including adjusting the operating mode of the chip, adjusting the operating parameters of the chip, and selecting the function. The chip working state electricity selection method can realize the adjustment operation of various working states on the chip under the condition of using few pins, and the control is accurate. And the resistance value processing circuit converts the resistance ratio analog signal into a digital signal, so that different resistance values have relatively unique digital signals corresponding to the digital signals, the possibility of misoperation is reduced, and the control accuracy is improved.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.