CN209525384U

CN209525384U - A kind of low-power dissipation power supply voltage detecting circuit of three-wire system

Info

Publication number: CN209525384U
Application number: CN201920083146.5U
Authority: CN
Inventors: 郑辉
Original assignee: Shenzhen Anmeitong Technology Co Ltd
Current assignee: Shenzhen Anmeitong Technology Co Ltd
Priority date: 2019-01-18
Filing date: 2019-01-18
Publication date: 2019-10-22
Anticipated expiration: 2029-01-18

Abstract

The utility model discloses a kind of low-power dissipation power supply voltage detecting circuits of three-wire system, including LDO voltage stabilizing chip, concatenated R1 and R2, the input termination power VBAT terminal of LDO, the VCC interface of the output termination MCU of LDO, a wherein termination VBAT terminal of R1, the SDA interface of another termination MCU of R1, the SCL interface of a termination MCU of R2, the A D interface of another termination MCU of another termination C1 of R2, C1.The low-power dissipation power supply voltage detecting circuit of the three-wire system, low-power consumption, simple using element in circuit, element occupies little space, and PCB design can be made to tend to minimize.

Description

A kind of low-power dissipation power supply voltage detecting circuit of three-wire system

Technical field

The utility model relates to detection circuits, and in particular to a kind of low-power dissipation power supply voltage detecting circuit of three-wire system.

Background technique

Currently used more low-power consumption battery voltage detection circuit (such as Fig. 5), supply voltage are greater than MCU input voltage When, cannot directly be sampled using A D interface, generally require and carry out voltage attenuation using triode or amplifier, then by AD into Row sampling, measures supply voltage.

A kind of low-power dissipation power supply voltage detecting circuit of three-wire system is proposed thus.

Utility model content

It is above-mentioned to solve the purpose of this utility model is to provide a kind of low-power dissipation power supply voltage detecting circuit of three-wire system The problem of being proposed in background technique.

To achieve the above object, the utility model provides the following technical solutions: a kind of low-power dissipation power supply voltage of three-wire system Detection circuit, including the input termination power VBAT terminal of LDO voltage stabilizing chip, concatenated R1 and R2, LDO, the output termination of LDO The VCC interface of MCU, wherein a termination VBAT terminal of R1, the SDA interface of another termination MCU of R1, the one of R2 terminate MCU's SCL interface, the A D interface of another termination MCU of another termination C1 of R2, C1.

Preferably, the capacity of the C1 is 200pF.

Preferably, the R1 and R2 is 47K Ω.

The technical effect and advantage of the utility model: the low-power dissipation power supply voltage detecting circuit of the three-wire system, low-power consumption, electricity Simple using element in road, element occupies little space, and PCB design can be made to tend to minimize.

Detailed description of the invention

Fig. 1 is the circuit diagram of the utility model；

Fig. 2 is that oscillograph measures SDA waveform diagram when circuit works；

Fig. 3 is that oscillograph measures SCL waveform diagram when circuit works；

Fig. 4 is that oscillograph measures AD sample waveform figure when circuit works；

Fig. 5 is conventional power source voltage detecting circuit figure.

Specific embodiment

The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work Every other embodiment obtained, fall within the protection scope of the utility model.

The utility model provides a kind of low-power dissipation power supply voltage detecting circuit of three-wire system as shown in Figure 1, including LDO The input termination power VBAT terminal of voltage stabilizing chip, concatenated R1 and R2, LDO, the VCC interface of the output termination MCU of LDO, A termination VBAT terminal of middle R1, the SDA interface of another termination MCU of R1, the SCL interface of a termination MCU of R2, R2's is another Terminate C1, the A D interface of another termination MCU of C1.

The capacity of the C1 is that 200pF, the R1 and R2 are 47K Ω.

Cell voltage is by switching to MCU available mains voltage value, this part is not included in after LDO voltage stabilizing chip in circuit In detection circuit, the supply voltage for only making signal measurement is greater than MCU input voltage.

Circuit theory: when circuit works, SDA interface, SCL interface and A D interface are such as schemed respectively in the waveform that oscillograph measures 2, shown in Fig. 3, Fig. 4, when MCU receives the order of battery voltage detection, first by SDA and SCL interface by being arranged simultaneously It is grounded (t1-t2), then sets open-drain state for SDA interface at the t2 moment, A D interface waveform rises at this time, when (t2-t3) The voltage that AD is sampled is the half of supply voltage, i.e. VAD=VBAT*R2/ (R1+R2) detects the voltage of this period, then Cell voltage just can be obtained by calculating.When not detecting usually, SDA and SCL are disposed as open-drain state, i.e., resistance is equal at this time For open-circuit condition, non-transformer consumption in circuit.

Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention, it is not limited to this Utility model, although the utility model is described in detail with reference to the foregoing embodiments, for those skilled in the art For, it is still possible to modify the technical solutions described in the foregoing embodiments, or to part of technical characteristic It is equivalently replaced, within the spirit and principle of the utility model, any modification, equivalent replacement, improvement and so on, It should be included within the scope of protection of this utility model.

Claims

1. a kind of low-power dissipation power supply voltage detecting circuit of three-wire system, including LDO voltage stabilizing chip, concatenated R1 and R2, LDO it is defeated Enter termination power VBAT terminal, the VCC interface of the output termination MCU of LDO, wherein the one of R1 terminates VBAT terminal, and R1's is another The SDA interface of MCU, the SCL interface of a termination MCU of R2 are terminated, the AD of another termination MCU of another termination C1 of R2, C1 connect Mouthful.

2. a kind of low-power dissipation power supply voltage detecting circuit of three-wire system according to claim 1, it is characterised in that: the C1 Capacity be 200pF.

3. a kind of low-power dissipation power supply voltage detecting circuit of three-wire system according to claim 1, it is characterised in that: the R1 It is 47K Ω with R2.