阅读说明：本技术 一种用于mcu的低温漂低压检测电路 (A kind of Low Drift Temperature low-voltage testing circuit for MCU ) 是由 冯旭 常成星 丁晓兵 胡锦通 黄鹏 于 2019-08-27 设计创作，主要内容包括：本发明涉及一种用于MCU的低温漂低压检测电路,属于集成电路技术领域。特征在于：包括一个正温度系数电阻、一个负温度系数的电阻、一个MOS管、一个比较器；其中正温度系数电阻的一端连接供电电压,另一端连接负温度系数电阻的一端和比较器的正输入端,向比较器的正输入端输出分压,负温度系数电阻的另一端接地；供电电压经过MOS管偏置,由MOS管向比较器的负输入端输出一个带负温度系数的电压,作为参考电压,通过调整参考电压的负温度系数和分压的负温度系数达到相等,使比较器输出零温漂的低电压检测电压,用于确保MCU的电压在低于低电压检测电压时可靠复位。本发明能生成零温漂的低电压检测电压,并能降低整个MCU的静态功耗。(The present invention relates to a kind of Low Drift Temperature low-voltage testing circuits for MCU, belong to technical field of integrated circuits.It is characterized in that: resistance, a metal-oxide-semiconductor, a comparator including a positive temperature coefficient resistor, negative temperature coefficient；Wherein one end of positive temperature coefficient resistor connects supply voltage, and the other end connects one end of negative temperature coefficient resister and the positive input terminal of comparator, exports and divides to the positive input terminal of comparator, the other end ground connection of negative temperature coefficient resister；Supply voltage is biased by metal-oxide-semiconductor, the voltage with negative temperature coefficient is exported from metal-oxide-semiconductor to the negative input end of comparator, as the reference voltage, reach equal by adjusting the negative temperature coefficient of reference voltage and the negative temperature coefficient of partial pressure, the low voltage test voltage for making comparator output zero temp shift, for ensuring the voltage of MCU reliable reset when lower than low voltage test voltage.The present invention can generate the low voltage test voltage of zero temp shift, and can reduce the quiescent dissipation of entire MCU.)

1. a kind of Low Drift Temperature low-voltage testing circuit for MCU, it is characterised in that: including positive temperature coefficient resistor R0, one The resistance R1 of a negative temperature coefficient, a metal-oxide-semiconductor M0, a comparator COMP；Wherein one end of positive temperature coefficient resistor R0 connects Supply voltage VDD is met, the other end connects one end of negative temperature coefficient resister and the positive input terminal of comparator, to the just defeated of comparator Enter end output partial pressure V1, the other end ground connection of negative temperature coefficient resister；Supply voltage is biased by metal-oxide-semiconductor, from metal-oxide-semiconductor to comparing The negative input end of device exports a voltage V with negative temperature coefficient_GS, V as the reference voltage_REF, by adjusting the negative of reference voltage Temperature coefficient and the negative temperature coefficient of partial pressure reach equal, make the low voltage test voltage of comparator output zero temp shift, for true The voltage of guarantor MCU reliable reset when being lower than low voltage test voltage.

2. being used for the Low Drift Temperature low-voltage testing circuit of MCU as described in claim 1, it is characterised in that: the metal-oxide-semiconductor uses N-channel MOS transistor or P channel MOS transistor, when using N-channel MOS transistor, source electrode ground connection, grid and drain are short It connects and is connect with the negative input end of bias current and comparator；When using P channel MOS transistor, grid and drain electrode are all connect Ground, source electrode connect bias current and connect with the negative input end of comparator.

3. being used for the Low Drift Temperature low-voltage testing circuit of MCU as described in claim 1, it is characterised in that: the partial pressure V1's Negative temperature coefficient is adjusted by the ratio of change positive temperature coefficient resistor R0 and the resistance R1 of negative temperature coefficient.

4. being used for the Low Drift Temperature low-voltage testing circuit of MCU as described in claim 1, it is characterised in that: the reference voltage V_REFNegative temperature coefficient by adjusting input mos transistor bias current I_dThe breadth length ratio W/L of size or MOS transistor comes Adjustment.

5. being used for the Low Drift Temperature low-voltage testing circuit of MCU as claimed in claim 4, it is characterised in that: the bias current I_d It extracts and generates from the biasing circuit of comparator.

Technical field

The present invention relates to a kind of Low Drift Temperature low-voltage testing circuits for MCU, belong to technical field of integrated circuits.

Background technique

MCU is a complicated system, including ROM, SRAM, SFR, ordering calculation unit and various peripheral hardwares.In order to be System reliablely and stablely works, and supply voltage VDD must be controlled within the scope of certain voltage.When voltage is too high, electricity can be damaged Road, voltage is too low, will lead to transistor and works abnormal, especially ROM, it may occur that the phenomenon that readout error.If it is some MCU on key equipment, such as demolition set occur system during power up or power down and execute mistake, will occur not Controllable explosion causes huge loss.

Low-voltage detection circuit is ensuring that MCU idle circuit at low voltage, when supply voltage is lower than some electricity When pressure, MCU stops working, and is in reset state.Supply voltage is only higher than this voltage MCU and just starts to work, and guarantees that MCU is steady Fixed reliable work.This voltage is commonly referred to as resetting voltage, and no matter the basic demand of resetting voltage is in what building ring All there can be no phenomenons not of uniform size under border.And temperature is affected to resetting voltage in general working environment, it is different The voltage that detects of temperature low-voltage detection circuit it is different, temperature drift is usually in this variation.In circuit design, temperature drift is one The index that a emphasis considers.

Currently used low-voltage detection circuit is to be divided with resistance to VDD mostly, is then produced with an individual circuit Raw reference voltage is compared, and thus leads to the problem of two, first is that the temperature drift of reference voltage directly determines that low-voltage is examined The temperature drift of slowdown monitoring circuit；Another problem is that generating circuit from reference voltage also has power consumption, and the power consumption of whole system is made to become larger.And The quiescent dissipation of MCU is an important index, and quiescent dissipation includes the operating current of each section circuit, it is therefore desirable to is suitable for The low-voltage testing circuit that a kind of operating current of MCU is small, temperature drift is small.

Summary of the invention

The object of the present invention is to provide a kind of Low Drift Temperature low-voltage testing circuit for MCU, feature is that operating current is small, temperature Float it is small, it is stable and reliable in work.

Technical solution is as follows:

A kind of Low Drift Temperature low-voltage testing circuit for MCU, including a positive temperature coefficient resistor R0, a negative temperature system Several resistance R1, a metal-oxide-semiconductor M0, a comparator COMP；Wherein one end of positive temperature coefficient resistor R0 connects supply voltage VDD, the other end connect one end of negative temperature coefficient resister and the positive input terminal of comparator, to the output point of the positive input terminal of comparator Press V1, the other end ground connection of negative temperature coefficient resister；Supply voltage is biased by metal-oxide-semiconductor, from metal-oxide-semiconductor to the negative input of comparator One voltage V with negative temperature coefficient of end output_GS, V as the reference voltage_REF, by adjusting reference voltage negative temperature coefficient and The negative temperature coefficient of partial pressure reaches equal, makes the low voltage test voltage of comparator output zero temp shift, for ensuring the voltage of MCU The reliable reset when being lower than low voltage test voltage.

Further, metal-oxide-semiconductor use N-channel MOS transistor or P channel MOS transistor, when use N-channel MOS transistor When, source electrode ground connection, grid and drain are shorted and connect with the negative input end of bias current and comparator；As use P-channel MOS When transistor, grid and drain electrode are all grounded, and source electrode connects bias current and connects with the negative input end of comparator.

Further, the negative temperature coefficient for dividing V1 passes through the resistance of change positive temperature coefficient resistor R0 and negative temperature coefficient The ratio of R1 adjusts.

Further, reference voltage V_REFNegative temperature coefficient by adjusting input mos transistor bias current I_dGreatly Small or MOS transistor breadth length ratio W/L is adjusted.

Further, bias current I_dIt extracts and generates from the biasing circuit of comparator.

The utility model has the advantages that

1) present invention divides supply voltage by the resistance of two different temperature coefficients, and generated with metal-oxide-semiconductor Reference voltage is compared, and the low voltage test voltage of zero temp shift can be generated.

It 2) can be by adjusting a variety of method adjustment such as resistance ratio, resistance temperature drift, bias current size and metal-oxide-semiconductor length-width ratio The temperature drift of circuit, more flexible simplicity, temperature drift are easier to control zero.

3) it does not need additional circuit and generates reference voltage, the quiescent dissipation of entire MCU can be reduced.

Detailed description of the invention

Fig. 1 is that the present invention makees the integrated circuit figure referred to using NMOS transistor；

Fig. 2 is that the present invention makees the integrated circuit figure referred to using PMOS transistor.

Wherein: R0 is positive temperature coefficient resistor, R1 is negative temperature coefficient resistance, M0 are metal-oxide-semiconductor, COMP be comparator, VDD is supply voltage, V1 is partial pressure, I_dFor bias current.

Specific embodiment

The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings:

A kind of Low Drift Temperature low-voltage testing circuit for MCU as shown in Figure 1, including positive temperature coefficient resistor R0, one The resistance R1 of a negative temperature coefficient, a metal-oxide-semiconductor M0, a comparator COMP；Wherein one end of positive temperature coefficient resistor R0 connects Supply voltage VDD is met, the other end connects one end of negative temperature coefficient resister and the positive input terminal of comparator, to the just defeated of comparator Enter end output partial pressure V1, the other end ground connection of negative temperature coefficient resister；Supply voltage is biased by metal-oxide-semiconductor, from metal-oxide-semiconductor to comparing The negative input end of device exports a voltage V with negative temperature coefficient_GS, V as the reference voltage_REF, by adjusting the negative of reference voltage Temperature coefficient and the negative temperature coefficient of partial pressure reach equal, make the low voltage test voltage of comparator output zero temp shift, for true The voltage of guarantor MCU reliable reset when being lower than low voltage test voltage.

Further, metal-oxide-semiconductor use N-channel MOS transistor or P channel MOS transistor, when use N-channel MOS transistor When, source electrode ground connection, grid and drain are shorted and connect with the negative input end of bias current and comparator；As use P-channel MOS When transistor, grid and drain electrode are all grounded, and source electrode connects bias current and connects with the negative input end of comparator.

Further, the negative temperature coefficient for dividing V1 passes through the resistance of change positive temperature coefficient resistor R0 and negative temperature coefficient The ratio of R1 adjusts, because the temperature coefficient of resistance is all smaller, the temperature change for dividing V1 is also not very big.But by making With the electric resistance partial pressure of two kinds of temperatures coefficient, it can effectively increase the temperature coefficient of V1.

Further, reference voltage V_REFNegative temperature coefficient by adjusting input mos transistor bias current I_dGreatly Small or MOS transistor breadth length ratio W/L is adjusted, bias current I_d=0.5* μ_n*C_ox*(W/L)*(V_GS-V_TH)², wherein C_oxIt is Unit gate capacitance size, W and L are the width and length, μ of MOS respectively_nIt is electron mobility, V can be derived by this formula_GSBy Threshold voltage V_THWith overload voltage V_OVTwo parts form, in following formula that open radical sign is exactly V_OV:

Threshold voltage V_THBand has plenty of negative temperature coefficient, and temperature coefficient is also larger, this is determined by technique itself, Circuit designers can not change, and overload voltage V_OVElectron mobility μ in formula_nIt is related with temperature, close to T^-3/2Mode subtract It is few, in I_dIn the case where fixation, V_OVIt is positive temperature coefficient, is adjusted by adjusting the W/L of MOS transistor；Or it is constant in W/L Under the premise of by I_dIt is designed to positive temperature coefficient, such V_OVAvailable biggish positive temperature coefficient, for offsetting V_THIt is negative Temperature coefficient reaches and adjusts V_GSTemperature coefficient target.

Further, bias current I_dIt extracts and generates from the biasing circuit of comparator.

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to restrict the invention, all in original of the invention Then with any modifications, equivalent replacements, and improvements made within spirit etc., should all be included in the protection scope of the present invention.