Battery power supply circuit for hardware switching

Abstract

The utility model relates to a battery power supply circuit for hardware switching. The battery power supply circuit comprises an external power supply circuit, a power failure meter reading power supply circuit and a clock power supply circuit which are electrically connected, the external power supply circuit is an external alternating current power supply end VMAIN +; an external alternating current power supply end VMAIN + is reversely connected with a voltage stabilizing diode DV4 and a divider resistor RV5 and then is divided into three paths, the first path is grounded through the divider resistor RV4, and the second path is electrically connected with a DVDD end through a switching diode DV1; the third path is connected with a PowerBatteryCtr point voltage clamp; the power failure meter reading power supply circuit comprises a power failure meter reading battery G2; a power failure meter reading battery G2 is connected with a pin 1 of an input end of a voltage stabilizer UQ2 through a switching diode DQ4; the pin 1 of the input end of the voltage stabilizer UQ2 and a pin 3 of an output end of the voltage stabilizer UQ2 are grounded through ceramic capacitors CU9 and CK4 respectively; a pin 3 of the output end of the voltage stabilizer UQ2 is electrically connected with a DVDD end by being connected with a PMOS tube QK6 and a switching diode DQ5; the device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to a battery power supply circuit for hardware switching. Background Art

[0002] Due to the needs of the working scene, the LCD screen of the smart meter sometimes needs to display continuously, which will put great pressure on the built-in battery of the meter and may shorten its service life. In order to solve this problem, a common practice is to use an external supercapacitor, additional battery or other backup power supply to extend the service life of the battery in the meter. During its use, the applicant discovered a technical problem - how to intelligently switch between external AC power supply, additional battery (or supercapacitor, energy storage power supply) and built-in battery.

[0003] In order to solve the above technical problems, first, the external AC power supply is automatically identified and used preferentially through the electric meter; secondly, the additional battery (or supercapacitor, energy storage power supply), and finally the built-in battery.

[0004] During the further research and development process, the applicant discovered that the technical problem is how to ensure the adaptability and stability of the switching circuit, taking into account the voltage and current differences of different power supplies. Finally, in order to meet the needs of long-term use, the switching circuit also needs to have low power consumption and high reliability.

[0005] To this end, an efficient battery switching circuit is needed.

[0006] There are two main ideas for realizing battery switching circuits: 1. Software detection control: This method relies on the microcontroller unit (MCU) to perform periodic power status checks and perform battery switching based on the results of the checks. However, a major disadvantage of this method is that it may not be able to respond to power changes instantly, resulting in delayed and unsmooth battery switching. 2. Discrete complex hardware logic control: This method uses complex hardware logic to directly control battery switching. Although it can provide a faster response speed, its disadvantages are also obvious: high power consumption, low voltage control accuracy, etc. Here, a circuit based on MOS tubes and voltage regulator tubes is proposed to realize hard switching of battery circuits. Utility Model Content

[0007] According to the background technology, for smart meters, first of all, the built-in battery of the smart meter does not need to be used frequently to reduce battery loss and extend its service life. Secondly, the power consumption of the entire device also needs to be effectively managed to ensure that the device can work continuously and stably. In the process of solving these problems, a key design point is the priority of external AC power supply, additional battery (supercapacitor or energy storage power supply) and built-in battery power supply. In order to ensure that the priority of these three power supplies is from high to low, a design scheme of a hardware-switched battery power supply circuit is designed. In general, the research on the hardware-switched battery power supply circuit of smart meters can not only improve the stability and life of the equipment, but also is expected to promote the development of the entire smart meter industry.

[0008] The technical problem to be solved by the utility model is generally to provide a battery power supply circuit for hardware switching.

[0009] In order to solve the above problems, the technical solution adopted by the utility model is:

[0010] In order to realize multi-channel power supply, it realizes power supply control through PMOS tube, gives priority to external power supply, a hardware-switched battery power supply circuit, the battery power supply circuit includes an electrically connected external power supply circuit, a power failure meter reading power supply circuit and a clock power supply circuit;

[0011] External power supply circuit, external AC power supply terminal VMAIN+; the external AC power supply terminal VMAIN+ is divided into three paths after being connected to the reverse voltage Zener diode DV4 and the voltage divider resistor RV5, the first path is grounded through the voltage divider resistor RV4, the second path is electrically connected to the DVDD terminal through the switch diode DV1; the third path is connected to the Power_Battery_Ctr point voltage clamp;

[0012] The power supply circuit for power failure meter reading includes a power failure meter reading battery G2; the power failure meter reading battery G2 is connected to the input terminal 1 pin of the voltage regulator UQ2 through the switching diode DQ4, the input terminal 1 pin and the output terminal 3 pin of the voltage regulator UQ2 are grounded through the ceramic capacitors CU9 and CK4 respectively; the output terminal 3 pin of the voltage regulator UQ2 is electrically connected to the DVDD terminal through the PMOS tube QK6 and the switching diode DQ5;

[0013] The G terminal of the PMOS tube QK6 is connected to Power_Battery_Ctr through the resistor RK22;

[0014] The clock power supply circuit includes a clock battery BAT2; the clock battery BAT2 is electrically connected to the DVDD terminal through a switching diode DQ11, a PMOS tube QK7, and a switching diode DQ12;

[0015] The G terminal of the PMOS tube QK7 is connected to Power_Battery_Ctr through the resistor RK23.

[0016] As a further improvement of the above technical solution:

[0017] In order to arrange reasonably and realize multiple strategy settings, the battery power supply circuit has a first power supply strategy state, a second power supply strategy state and a third power supply strategy state.

[0018] The first power supply strategy state is that the external power supply circuit, the power outage meter reading battery G2, and the clock battery BAT2 are connected at the same time;

[0019] The external power supply circuit is turned on and is in a state of supplying power to MVDD;

[0020] In the PMOS tube QK6, the G-pole voltage clamping voltage is greater than the S-pole voltage, the on-state voltage drop VGS>VGS(th), the PMOS tube QK6 is in the cut-off state, and the power-off meter reading battery G2 is in the state of stopping power supply to MVDD;

[0021] In the PMOS tube QK7, the G-pole voltage clamping voltage is greater than the S-pole voltage, the on-state voltage drop VGS>VGS(th), the PMOS tube QK7 is in the cut-off state, and the clock battery BAT2 is in the state of stopping power supply to MVDD.

[0022] The second power supply strategy state is that the smart meter has no external power supply circuit, and the power failure meter reading battery G2 and the clock battery BAT2 are connected at the same time;

[0023] The voltage at the Power_Battery_Ctr point is at a low level, and the clock battery BAT2 and the battery power failure meter reading battery G2 are in the state of supplying power to MVDD;

[0024] In the PMOS tube QK6, the G-pole voltage clamping voltage is less than the S-pole voltage, the on-state voltage drop VGS<VGS(th), and the PMOS tube QK6 is in the on state.

[0025] At this time, the G pole voltage of QK7 is 0V, and the S pole voltage is 3.4V. At this time, the conduction voltage drop of the PMOS tube VGS>VGS(th), and the PMOS tube is in the conduction state;

[0026] When the power supply voltage of the power-off meter reading battery G2 to MVDD is greater than the power supply voltage of the clock battery BAT2 to MVDD, the power-off meter reading battery G2 is in the state of supplying power to MVDD.

[0027] The third power supply strategy state is that the smart meter has no external power supply circuit, and the power failure meter reading battery G2 and the clock battery BAT2 are connected to one of them;

[0028] When the power outage meter reading battery G2 is in a single state, the G pole voltage of the PMOS tube QK6 is 0V, the conduction voltage drop VGS of the PMOS tube QK6 is less than VGS(th), and the power outage meter reading battery G2 is in a state of supplying power to MVDD;

[0029] When the power outage meter reading battery G2 is in the state of being alone,

[0030] The clock battery BAT2 is divided by DQ11 and DQ12 to supply power to MVDD.

[0031] The G-pole voltage of the PMOS tube QK7 is 0V, the on-state voltage drop VGS of the PMOS tube QK7 is greater than VGS(th), the PMOS tube is in the on state, and the clock battery BAT2 is in the state of supplying power to MVDD.

[0032] The utility model controls the on and off of the power supply through a hardware control method, which can save the I / O port resources of the MCU. The external power input range is wide, and the VMAIN+ input range can be expanded within a certain range by adjusting the voltage stabilization value of DV4 and the resistance value of RV5 and RV6, which has high flexibility. Low power consumption, compared with traditional hardware logic control, the switch solution based on MOS tube has lower power consumption and can extend the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0034] like Figure 1 As shown, the battery power supply circuit of the hardware switching of this embodiment includes the following components:

[0035] CU9 and CK4 are ceramic capacitors, which provide energy storage and filtering in the circuit;

[0036] QK6 and QK7 are PMOS tubes, which act as switches in the circuit; DV4 is a voltage regulator diode, DV1 is a switching diode, and RV4 and RV5 are SMD thick film resistors. With the joint action of these devices, the circuit is stabilized when only AC power is supplied; G2 and BAT2 are 6V power failure meter reading battery and 3.6V clock battery respectively, and the devices act as power supply in the circuit; DQ4, DQ5, DQ11, and DQ12 are switching diodes, which act as voltage reducers and current backflow prevention in the circuit; UQ2 is an LDO, which acts as a voltage converter in the circuit; RK3, RK4, RK9, and RK10 are SMD thick film resistors, which divide the battery voltage in the circuit, and the divided voltage is sampled by the MCU and converted into battery voltage data. This function can identify whether the battery exists and detect the battery power.

[0037] The working process of the hardware-switched battery-powered circuit can be divided into the following situations:

[0038] 1. When the smart meter is powered by external AC power, and the power failure meter reading battery and the built-in clock battery exist at the same time, the switch is as follows:

[0039] 1.1. VMAIN+ is powered by external AC power. After being stabilized at 6.8V by DV4, the remaining voltage is divided by voltage-dividing resistors RV4 and RV5. DVDD is an external constant voltage of 3.3V. The voltage at Power_Battery_Ctr point is clamped at about 4V by DV1. At this time, MVDD is powered by an external power supply.

[0040] 1.2. G2 is the battery for power outage meter reading. It is converted into 3.3V voltage by UQ2 and DQ5 for power supply. At this time, the G pole voltage of QK6 is clamped to about 4V, and the S pole voltage is 3.6V. At this time, the conduction voltage drop of the PMOS tube VGS>VGS(th), the PMOS tube is in the cut-off state, and the G2 battery cannot supply power to MVDD.

[0041] 1.3. BAT2 is the clock battery, which is powered by MVDD through voltage division of DQ11 and DQ12.

[0042] At this time, the G-pole voltage of QK7 is clamped to about 4V, and the S-pole voltage is 3.4V. At this time, the on-state voltage drop of the PMOS tube VGS>VGS(th), the PMOS tube is in the cut-off state, and the BAT2 battery cannot supply power to MVDD.

[0043] 2. When the smart meter has no external AC power supply, and the power outage meter reading battery and the built-in clock battery exist at the same time, the switch is as follows:

[0044] 2.1. When the external AC power is not supplied, the voltage at the Power_Battery_Ctr point is at a low level of about 0V, and the G2 battery is used to supply power to the MVDD.

[0045] 2.2. G2 is the battery for power meter reading during power outages. It is converted into a 3.3V voltage by UQ2 and DQ5 for power supply. At this time, the G pole voltage of QK6 is 0V and the S pole voltage is 3.6V. At this time, the conduction voltage drop of the PMOS tube VGS<VGS(th), the PMOS tube is in the on state, and the G2 battery supplies power to MVDD.

[0046] 2.3. BAT2 is the clock battery, which is powered by MVDD through voltage division of DQ11 and DQ12.

[0047] At this time, the G pole voltage of QK7 is 0V, and the S pole voltage is 3.4V. At this time, the on-state voltage drop of the PMOS tube VGS<VGS(th), and the PMOS tube is in the on state. The BAT2 battery supplies power to MVDD. By configuring the on-state voltage drop of DQ5, DQ11, and DQ12, the voltage when G2 is supplying power is greater than the voltage when BAT2 is supplying power. The two compete with each other, and at this time, the G2 power outage meter reading battery is used for power supply.

[0048] 3. When the smart meter has no external AC power supply, the power outage meter reading battery and

[0049] When one of the built-in clock batteries is present, the switch is as follows:

[0050] 3.1. G2 is the battery for power outage meter reading. When G2 battery exists alone, it is converted into 3.3V voltage through UQ2 and DQ5 for power supply. At this time, the G pole voltage of QK6 is 0V, and the S pole voltage is 3.6V. At this time, the conduction voltage drop of PMOS tube VGS<VGS(th), PMOS tube is in the on state, and G2 power outage meter reading battery supplies power to MVDD.

[0051] 3.2. BAT2 is the clock battery, which is powered by MVDD through voltage division of DQ11 and DQ12.

[0052] At this time, the G pole voltage of QK7 is 0V, and the S pole voltage is 3.4V. At this time, the conduction voltage drop of the PMOS tube VGS>VGS(th), the PMOS tube is in the on state, and the BAT2 battery supplies power to MVDD.

[0053] The utility model is a hardware switching battery power supply circuit for electric energy meters in the field of smart electric meters; when the circuit realizes multi-power supply, the priority is the external power supply priority, the power failure meter reading battery is the second, and the built-in clock battery is the lowest, so as to achieve the most reasonable application of the built-in battery power consumption. When three different power supplies are supplied, the conduction and shutdown of PMOS tubes QK6 and QK7 are controlled by reasonable circuit design to realize the priority power supply of each power supply. External AC power supply circuit control mode; through the design of series voltage regulator tube DV4, switch tube DV1, resistors RV4 and RV5, G-level control of PMOS tubes QK6 and QK7 is realized to realize the conduction control of QK6 and QK7; the power failure meter reading battery and clock battery power supply circuit control mode, by configuring the conduction voltage drop of diodes DQ5, DQ11, and DQ12, the competition relationship between the two power supplies is allocated, thereby realizing the power priority after the electric energy meter is powered off. Qk6 and Qk7 parallel control mode: The control of this circuit adopts the parallel mode of QK6 and QK7 to realize the power supply when the external power supply exists (does not exist).

[0054] The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it; although the utility model is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the utility model. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. A hardware-switched battery-powered circuit, characterized in that: The battery power supply circuit includes an electrically connected external power supply circuit, a power failure meter reading power supply circuit and a clock power supply circuit; External power supply circuit, external AC power supply terminal VMAIN+; the external AC power supply terminal VMAIN+ is divided into three paths after being connected to the reverse voltage Zener diode DV4 and the voltage divider resistor RV5, the first path is grounded through the voltage divider resistor RV4, the second path is electrically connected to the DVDD terminal through the switch diode DV1; the third path is connected to the Power_Battery_Ctr point voltage clamp; The power supply circuit for power failure meter reading includes a power failure meter reading battery G2; the power failure meter reading battery G2 is connected to the input terminal 1 pin of the voltage regulator UQ2 through the switching diode DQ4, the input terminal 1 pin and the output terminal 3 pin of the voltage regulator UQ2 are grounded through the ceramic capacitors CU9 and CK4 respectively; the output terminal 3 pin of the voltage regulator UQ2 is electrically connected to the DVDD terminal through the PMOS tube QK6 and the switching diode DQ5; The G terminal of the PMOS tube QK6 is connected to Power_Battery_Ctr through the resistor RK22; The clock power supply circuit includes a clock battery BAT2; the clock battery BAT2 is electrically connected to the DVDD terminal through a switching diode DQ11, a PMOS tube QK7, and a switching diode DQ12; The G terminal of the PMOS tube QK7 is connected to Power_Battery_Ctr through the resistor RK23.

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