CN113341333A

CN113341333A - Low-power consumption power supply detection circuit

Info

Publication number: CN113341333A
Application number: CN202110544499.2A
Authority: CN
Inventors: 杨保顶
Original assignee: IPGoal Microelectronics Sichuan Co Ltd
Current assignee: IPGoal Microelectronics Sichuan Co Ltd
Priority date: 2021-05-19
Filing date: 2021-05-19
Publication date: 2021-09-03

Abstract

The invention discloses a low-power-consumption power supply detection circuit, which comprises a current source, a voltage division switch starting circuit, a voltage division circuit and an ADC (analog to digital converter) sampling equivalent circuit, wherein external control signals are respectively input into the voltage division switch starting circuit and the voltage division circuit; the power supply voltage is input into the current source, and the current source provides bias current for the whole circuit; the voltage division switch starting circuit is respectively connected with a power supply voltage, a detection voltage, a voltage division circuit and a current source and provides a starting voltage for the voltage division circuit; the voltage division circuit is further connected with the detection voltage so as to provide divided voltage for the ADC sampling equivalent circuit, and the ADC sampling equivalent circuit outputs the voltage value obtained by sampling. The low-power-consumption power supply detection circuit disclosed by the invention has the advantages of few used devices, simple circuit structure and low power consumption, and overcomes the problem of poor withstand voltage.

Description

Low-power consumption power supply detection circuit

Technical Field

The invention relates to the field of integrated circuits, in particular to a low-power-consumption power supply detection circuit.

Background

The power detection circuit is an indispensable component in modern electronic products, and the low-power-consumption and low-cost design thereof is increasingly important. In low-cost design of an integrated circuit, a conventional device design is often adopted, such as a 3.3V IO device design, and the supply range of the detection voltage VBAT is often 5V or higher. For a power supply part higher than 3.3V, a voltage withstanding design is needed, namely, when the work and the circuit are turned off, the gate source voltage | VGS |, the gate drain voltage | VGD |, and the source drain voltage | VSD | of all COMS devices in the circuit are all in a voltage range required by the process, for example, 3.3V IO devices, the voltage is required to be in a range of 3.3V +/-10% by the general process, otherwise, the service life is reduced, the electric leakage is caused, or the work is abnormal.

Specifically, as shown in fig. 1, VBAT is a high voltage to be detected (power voltage is greater than 5V), R1 and R2 are two voltage dividing resistors, OPA is an operational amplifier, power supply voltage AVD is 3.3V, OPA is a connection mode of a buffer, and an output of OPA is connected to the ADC circuit.

The working principle is as follows:

the voltage is divided by the resistors R1 and R2 to obtain a divided voltage VDIV, VBAT × R2/(R1+ R2), in order to avoid the problem of voltage withstanding, the divided voltage VDIV must be less than 3.3V while satisfying the input voltage range of the OPA, and the divided voltage is connected by the buffer connection means to obtain an output voltage VDIVO, VDIV + VOS, where VOS is the offset voltage of the OPA. The output voltage VDIVO is decoded by the ADC to obtain digital data VDATA after the VDIVO is decoded, and therefore the voltage value of the voltage VBAT to be measured is calculated.

However, the power supply detection circuit has the following problems:

1. the design is more complex, the operational amplifier circuit OPA with the more complex design is included, and strict requirements on the input voltage range, noise, offset and the like of the operational amplifier OPA are met;

2. in order to prevent the occurrence of voltage resistance, a resistor voltage division branch cannot design a switching circuit by a conventional 3.3V CMOS device, otherwise, the voltage resistance problem of a switching tube occurs when the circuit is turned off, so that the current of the voltage division branch always exists and low-power-consumption processing cannot be realized;

3. in order to reduce the power consumption in the use, often can intermittent type formula switch operational amplifier OPA, operational amplifier OPA needs certain start-up time, before ADC samples, need guarantee its normal start and sample again after stable, and the power consumption of circuit has further been increased to the opening time of op-amp.

Therefore, it is necessary to provide a low power consumption power detection circuit with higher detection accuracy and lower power consumption to overcome the above-mentioned drawbacks.

Disclosure of Invention

The invention aims to provide a low-power-consumption power supply detection circuit which has the advantages of fewer used devices, simple circuit structure, low power consumption and capability of overcoming the problem of poor voltage resistance.

The invention discloses a low-power-consumption power supply detection circuit, which comprises a current source, a voltage division switch starting circuit, a voltage division circuit and an ADC (analog to digital converter) sampling equivalent circuit, wherein external control signals are respectively input into the voltage division switch starting circuit and the voltage division circuit; the power supply voltage is input into the current source, and the current source provides bias current for the whole circuit; the voltage division switch starting circuit is respectively connected with a power supply voltage, a detection voltage, a voltage division circuit and a current source and provides a starting voltage for the voltage division circuit; the voltage division circuit is further connected with the detection voltage so as to provide divided voltage for the ADC sampling equivalent circuit, and the ADC sampling equivalent circuit outputs the voltage value obtained by sampling.

Preferably, the voltage division switch starting circuit comprises a first field effect transistor, a second field effect transistor, a third field effect transistor, a fourth field effect transistor and a first resistor; the first field effect transistor and the second field effect transistor form a mirror image current mirror circuit, the drain electrode of the first field effect transistor is connected with the current source, and the drain electrode of the second field effect transistor is connected with the source electrode of the third field effect transistor; an external control signal is input into a grid electrode of the third field effect transistor, and a drain electrode of the third field effect transistor is connected with a source electrode of the fourth field effect transistor; and power voltage is input into the grid electrode of the fourth field effect transistor, the drain electrode of the fourth field effect transistor is connected with one end of the first resistor, and the other end of the first resistor is connected with the detection voltage.

Preferably, the first field effect transistor and the second field effect transistor form a mirror current mirror circuit, which specifically includes: the drain electrode and the grid electrode of the first field effect tube are connected with the grid electrode of the second field effect tube, and the source electrodes of the first field effect tube and the second field effect tube are grounded.

Preferably, the voltage dividing circuit includes a fifth field effect transistor, a sixth field effect transistor, a second resistor and a third resistor; an external control signal is input into a grid electrode of the fifth field effect transistor, a source electrode of the fifth field effect transistor is grounded, and a drain electrode of the fifth field effect transistor is connected with one end of the second resistor; the other end of the second resistor is respectively connected with the ADC sampling equivalent circuit and one end of a third resistor; the other end of the third resistor is connected with the drain electrode of the sixth field effect transistor, the grid electrode of the sixth field effect transistor is connected with one end of the first resistor, and the detection voltage is input into the source electrode of the sixth field effect transistor.

Preferably, the third field effect transistor and the fifth field effect transistor are both switching transistors, and the fourth field effect transistor is an anti-voltage transistor.

Preferably, the voltage value VP at one end of the first resistor satisfies the following relationship:

VBAT-3.3V≤Vp≤3.3V；

wherein VBAT is a voltage value of the detection voltage, and 3.3V is a withstand voltage value of each field effect transistor.

Preferably, the first field effect transistor, the second field effect transistor, the third field effect transistor, the fourth field effect transistor and the fifth field effect transistor are all N-type field effect transistors, and the sixth field effect transistor is a P-type field effect transistor.

Compared with the prior art, the low-power-consumption power supply detection circuit has the advantages that the operational amplifier is not used in the whole circuit, so that the whole circuit can be realized by using fewer devices, the circuit structure is simple, and the corresponding power consumption is reduced; in addition, the voltage division circuit is also connected with the detection voltage, so that the higher detection voltage is divided, the influence of poor withstand voltage on each device in the circuit is avoided, and the problem of poor withstand voltage in the circuit is solved.

The invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, which illustrate embodiments of the invention.

Drawings

Fig. 1 is a circuit configuration diagram of a power detection circuit of the related art.

Fig. 2 is a circuit structure diagram of the low power consumption power detection circuit of the present invention.

Detailed Description

Embodiments of the present invention will now be described with reference to the drawings, wherein like element numerals represent like elements. As described above, the low power consumption power detection circuit provided by the invention has the advantages of fewer used devices, simple circuit structure, low power consumption and capability of overcoming the problem of poor withstand voltage.

Referring to fig. 2, fig. 2 is a circuit diagram of the low power consumption power detection circuit of the present invention. As shown in the figure, the low-power consumption power supply detection circuit of the invention comprises a current source IS, a voltage division switch starting circuit, a voltage division circuit and an ADC sampling equivalent circuit; an external control signal EN is respectively input into the voltage division switch starting circuit and the voltage division circuit; the power supply voltage AVD IS input into the current source IS, and the current source IS provides bias current for the whole circuit; the voltage division switch starting circuit IS respectively connected with the power supply voltage AVD, the detection voltage VBAT, the voltage division circuit and the current source IS, and provides a starting voltage V for the voltage division circuit_P(ii) a The voltage division circuit is also connected with the detection voltage VBAT so as to provide the divided voltage V for the ADC sampling equivalent circuit_DIVAnd the ADC sampling equivalent circuit outputs a voltage value obtained by sampling (not shown). The bias current circuit IS a necessary circuit in system design, and provides various bias currents for each module in a system branch, and only one branch of the bias current circuit (namely the branch where the current source IS) IS used in the low-power-consumption power supply detection circuit of the invention, so that no additional circuit IS added. As described above, in the invention, because the operational amplifier is not used in the whole circuit, the whole circuit can be realized by using fewer devices, the circuit structure is simple, and the corresponding power consumption is also reduced; in addition, the voltage division circuit is also connected with the detection voltage, so that the higher detection voltage is divided, the influence of poor withstand voltage on each device in the circuit is avoided, and the problem of poor withstand voltage possibly existing in the circuit is solved.

Specifically, in the present invention, the voltage dividing switch turn-on circuit includes a first fet M1, a second fet M2, a third fet M3, a fourth fet M4, and a first resistor R1; the first field-effect transistor M1 and the second field-effect transistor M2 form a mirror-image current mirror circuit, specifically, a drain and a gate of the first field-effect transistor M1 are commonly connected with a gate of the second field-effect transistor M2, and sources of the first field-effect transistor M1 and the second field-effect transistor M2 are both grounded; the drain of the first field effect transistor M1 IS connected with the current source IS, and the drain of the second field effect transistor M2 IS connected with the source of the third field effect transistor M3; the first field effect transistor M1 and the second field effect transistor M2 form a mirror current mirror circuit, which specifically includes: the drain and the gate of the first field effect transistor M1 are commonly connected with the gate of the second field effect transistor M2, and the sources of the first field effect transistor M1 and the second field effect transistor M2 are both grounded. An external control signal EN is input into the grid electrode of the third field effect transistor M3, and the drain electrode of the third field effect transistor M3 is connected with the source electrode of the fourth field effect transistor M4; the power voltage AVD is inputted to the gate of the fourth fet M4, the drain of the fourth fet M4 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the detection voltage VBAT. Under the action of the mirror current mirror circuit, assuming that the ratio of the width to length of the second fet M2 to the first fet M1 is K, the current I2 is K × I1. In a preferred embodiment of the present invention, the third fet M3 and the fifth fet M5 are switching transistors, the fourth fet M4 is a voltage-proof transistor, each switching transistor is turned on when the control signal EN is a high level AVD, each switching transistor is turned off when the control signal EN is a low level 0, and the power supply voltage AVD is directly input to the gate of the fourth fet M4, so that the voltage drop of the first resistor R1 with respect to the detection voltage VBAT is:

V_DR1＝VBAT-Vp＝I2×R1＝K×I1×R1。

in the present invention, further, the voltage divider circuit includes a fifth fet M5, a sixth fet M6, a second resistor R2 and a third resistor R3; an external control signal EN is input into the grid electrode of the fifth field effect transistor M5, the source electrode of the fifth field effect transistor M5 is grounded, and the drain electrode of the fifth field effect transistor M5 is connected with one end of the second resistor R2; the other end of the second resistor R2 is respectively connected with the ADC sampling equivalent circuit and one end of a third resistor R3; the other end of the third resistor R3 is connected to the drain of the sixth fet M6, the gate of the sixth fet M6 is connected to one end of the first resistor R1, and the detection voltage VBAT is input to the source of the sixth fet M6. As a preferred embodiment of the present inventionThe third fet M3 and the fifth fet M5 are both switching transistors, and the fourth fet M4 is a voltage-proof transistor. In the invention, a voltage drop is generated after the current I2 passes through the first resistor R1, the voltage drop is the turn-on voltage of the sixth field-effect transistor M6, and the gate-source voltage | V of the sixth field-effect transistor M6 needs to be ensured during design_SGM6I is sufficiently large and satisfies:

VBAT-3.3V≤Vp≤3.3V；

wherein 3.3V is the withstand voltage value of each field effect transistor; therefore, the opening of the sixth field effect transistor M6 is ensured, the problem of poor voltage resistance of each field effect transistor is also prevented, and the stable operation of the whole circuit is ensured.

In addition, in order to ensure the stability and accuracy of the low power consumption power detection circuit of the present invention, it is particularly set that the first fet M1, the second fet M2, the third fet M3, the fourth fet M4, and the fifth fet M5 are all N-type fets, and the sixth fet M6 is a P-type fet.

In the ADC sampling equivalent circuit, Ron is an equivalent impedance when a sampling switch of the ADC sampling circuit is closed, and Cs is an equivalent capacitance when the ADC sampling circuit samples, which will not be described in detail herein.

In the following, referring to fig. 2, the working principle of the low power consumption power detection circuit of the present invention is described:

when the control signal EN is the high level AVD, the third fet M3 and the fifth fet M5, which are switching tubes, are turned on, the current I1 generates the current I2 through a mirror circuit formed by the first fet M1 and the second fet M2, and the current I2 generates a voltage drop after passing through the first resistor R1, where the voltage drop is the turn-on voltage of the sixth fet M6. In the application process, the grid-source voltage | V of the sixth field effect transistor M6 needs to be ensured_SGM6I is large enough and satisfies

VBAT-3.3V≤Vp≤3.3V

Wherein 3.3V is the voltage endurance of each FET, Vp1 and Vp2 are less than 3.3V because Vp is less than or equal to 3.3V, and Vp3 is also less than 3.3V because M1 is supplied by AVD.

At this time, the sixth fet M6 may be equivalent to a switching tube with very low impedance, and the gate-source voltage, the drain-source voltage, and the gate-drain voltage of each of M4, M3, and M2 are as follows:

|V_GSM4|＝|AVD-Vp1|＜3.3V

|V_DSM4|＝|Vp-Vp1|＜3.3V

|V_GDM4|＝|Vp-AVD|＜3.3V

|V_GSM3AVD-Vp2| < 3.3V (and EN high level AVD)

|V_DSM3|＝|Vp1-Vp2|＜3.3V

|V_GDM3|＝|Vp-AVD|＜3.3V

|V_GSM2|＝|Vp3|＜3.3V

|V_DSM4|＝|Vp2|＜3.3V

|V_GDM4|＝|Vp2-Vp3|＜3.3V

Therefore, the gate-source voltage, the drain-source voltage and the gate-drain voltage of the fourth field-effect tube M4, the third field-effect tube M3 and the second field-effect tube M2 are all within 3.3V, and the problem of poor withstand voltage caused by the high voltage of the detection voltage VBAT is solved.

Wherein the sixth field effect transistor M6 equivalent resistance R_OM6The resistance values are as follows:

wherein kp is the technological parameter of the P type MOS device, (W/L)_M6Is the width-to-length ratio, V, of the sixth field effect transistor M6_THM6Is the threshold voltage of the sixth fet M6.

When the control signal EN is high (AVD), the fifth fet M5 is also a switch tube, and its equivalent impedance is

Wherein kn is the process parameter of the N-type MOS device, (W/L)_M5Is the width-to-length ratio, V, of the fifth field effect transistor M5_THM5Is a fifth field effect transistor M5The threshold voltage of (2).

The impedances of the sixth fet M6 and the fifth fet M5 as switching tubes are very small and much smaller than the second resistor R2 and the third resistor R3, but the output voltage V of the voltage divider circuit is obtained_DIVThe precision can be considered by design, and

thereby dividing the voltage V_DIVMore accurate, then the voltage is divided

The second resistor R2 and the third resistor R3 are designed to easily ensure the output voltage V of the voltage divider circuit_DIVIn the normal working voltage and input range of the ADC sampling circuit, the grid-source voltage, the drain-source voltage and the grid-drain voltage of the sixth field-effect tube M6 and the fifth field-effect tube M5 are all within 3.3V, and the problem of poor withstand voltage caused by the high voltage of the detection voltage VBAT is solved.

At design time, guarantee time constant [ (R3+ R)_ONM6)//(R2+R_ONM5)]Cs satisfies voltage detection precision, and robustness of circuit design can be guaranteed within an effective precision range of the ADC sampling circuit.

When the control signal EN is at the low level 0, the third fet M3 and the fifth fet M5, which are switching tubes, are turned off, and at this time, since the gate of the fourth fet M4 of the voltage-proof tube is connected to the power supply voltage AVD, and the third fet M3 is turned off, the high-impedance state is obtained, the impedance of the high-impedance state is much greater than the impedance of the first resistor R1, and the voltage value of the voltage Vp is the detection voltage VBAT.

The gate of the fourth field effect transistor M4 is connected with the power supply voltage AVD

Vp1＝AVD-V_GSM4，

Ensuring that Vp-Vp1 is less than or equal to 3.3V during design, namely VBAT-AVD + V_GSM4Less than or equal to 3.3VThe drain-source voltage, the gate-source voltage and the gate-drain voltage of the fourth field effect transistor M4 are all within the range of the power supply voltage AVD. The sum of the drain-source voltages of the second FET M2 and the third FET M3 is AVD-V_GSM4And the voltage is lower than the power supply voltage AVD, so that the drain-source voltage, the gate-source voltage and the gate-drain voltage of the second field-effect tube M2 and the third field-effect tube M3 are all in the range of the power supply voltage AVD, and the problem of voltage resistance can be avoided. Meanwhile, as the voltage of the node VP is the detection voltage VBAT, the voltage of the control signal EN is 0, the fifth field effect transistor M5 and the sixth field effect transistor M6 are both turned off, and the output voltage V of the voltage division circuit_DIVAt this time, the voltage is divided by the second resistor R2 and the third resistor R3, so that the drain-source voltages of the fifth field-effect transistor M5 and the sixth field-effect transistor M6 are easily within the range of the power supply voltage AVD, and the gate-source voltage and the gate-drain voltage are also ensured within the range of the power supply voltage AVD.

Therefore, in the invention, the conventional COMS device can be ensured not to have the withstand voltage problems of drain-source voltage, gate-source voltage and gate-drain voltage no matter the control signal EN is in high level and the circuit works normally, or the control signal EN is in low voltage and the circuit is closed. And power consumption is calculated as follows:

assuming that the sampling time of the ADC sampling circuit is TS, and during sampling, the control signal EN is at a high level, ignoring the switching impedances of the fifth fet M5 and the sixth fet M6, and at this time, the power consumption of the circuit is:

when the actual circuit is applied, the voltage detection does not need to be always detected, the working mode is intermittent detection, namely after one-time detection is finished, the voltage is detected again after a period of time, and if the detection interval time is TP, the average power consumption I of the detection circuit is_RMSIs composed of

In practical applications, samplingTime TS is of the order of microseconds and interval time TP is of the order of seconds, I_TSThe power consumption is in milliamp magnitude, and the average power consumption is in nanoamp magnitude after calculation, so the power consumption is extremely low.

In summary, the low power consumption power detection circuit of the invention is realized by using fewer devices because no operational amplifier is used in the whole circuit, the circuit structure is simple, and the corresponding power consumption is also reduced; in addition, the voltage division circuit is also connected with the detection voltage, so that the higher detection voltage is divided, the influence of poor withstand voltage on each device in the circuit is avoided, and the problem of poor withstand voltage in the circuit is solved.

The present invention has been described in connection with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, and is intended to cover various modifications, equivalent combinations, which are made in accordance with the spirit of the present invention.

Claims

1. A low-power consumption power supply detection circuit is characterized by comprising a current source, a voltage division switch starting circuit, a voltage division circuit and an ADC (analog to digital converter) sampling equivalent circuit, wherein external control signals are respectively input into the voltage division switch starting circuit and the voltage division circuit; the power supply voltage is input into the current source, and the current source provides bias current for the whole circuit; the voltage division switch starting circuit is respectively connected with a power supply voltage, a detection voltage, a voltage division circuit and a current source and provides a starting voltage for the voltage division circuit; the voltage division circuit is further connected with the detection voltage so as to provide divided voltage for the ADC sampling equivalent circuit, and the ADC sampling equivalent circuit outputs the voltage value obtained by sampling.

2. The power detection circuit with low power consumption of claim 1, wherein the voltage dividing switch turn-on circuit comprises a first field effect transistor, a second field effect transistor, a third field effect transistor, a fourth field effect transistor and a first resistor; the first field effect transistor and the second field effect transistor form a mirror image current mirror circuit, the drain electrode of the first field effect transistor is connected with the current source, and the drain electrode of the second field effect transistor is connected with the source electrode of the third field effect transistor; an external control signal is input into a grid electrode of the third field effect transistor, and a drain electrode of the third field effect transistor is connected with a source electrode of the fourth field effect transistor; and power voltage is input into the grid electrode of the fourth field effect transistor, the drain electrode of the fourth field effect transistor is connected with one end of the first resistor, and the other end of the first resistor is connected with the detection voltage.

3. The low power consumption power detection circuit according to claim 2, wherein the first field effect transistor and the second field effect transistor form a mirror current mirror circuit, specifically: the drain electrode and the grid electrode of the first field effect tube are connected with the grid electrode of the second field effect tube, and the source electrodes of the first field effect tube and the second field effect tube are grounded.

4. The low power consumption power detection circuit according to claim 2, wherein the voltage divider circuit comprises a fifth field effect transistor, a sixth field effect transistor, a second resistor and a third resistor; an external control signal is input into a grid electrode of the fifth field effect transistor, a source electrode of the fifth field effect transistor is grounded, and a drain electrode of the fifth field effect transistor is connected with one end of the second resistor; the other end of the second resistor is respectively connected with the ADC sampling equivalent circuit and one end of a third resistor; the other end of the third resistor is connected with the drain electrode of the sixth field effect transistor, the grid electrode of the sixth field effect transistor is connected with one end of the first resistor, and the detection voltage is input into the source electrode of the sixth field effect transistor.

5. The power detection circuit with low power consumption of claim 4, wherein the third field effect transistor and the fifth field effect transistor are both switching transistors, and the fourth field effect transistor is a voltage-proof transistor.

6. The power detection circuit with low power consumption of claim 5, wherein the voltage value VP at one end of the first resistor satisfies the following relationship:

VBAT-3.3V≤Vp≤3.3V；

7. The power detection circuit with low power consumption of claim 4, wherein the first field effect transistor, the second field effect transistor, the third field effect transistor, the fourth field effect transistor and the fifth field effect transistor are all N-type field effect transistors, and the sixth field effect transistor is a P-type field effect transistor.