Power failure detection and battery switching control circuit

Abstract

The utility model relates to a power supply power failure detection and battery switching control circuit, which comprises a main power supply power failure detection circuit, an auxiliary power supply power failure detection circuit, a battery switching control circuit and a battery power supply circuit, wherein the main power supply power failure detection circuit is used for detecting whether a main power supply is powered down or not; the auxiliary power supply power-down detection circuit is used for detecting whether the auxiliary power supply is powered down; the battery switching circuit is used for controlling a battery circuit switch; the battery power supply circuit supplies power to a load by a battery; the main power supply power failure detection circuit and the auxiliary power supply power failure detection circuit are electrically connected with the input end of the battery switching control circuit respectively; the output end of the battery switching control circuit is electrically connected with the input end of the battery power supply circuit. The device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to a power failure detection and battery switching control circuit, in particular to a dual-circuit power failure detection and battery switching control circuit. Background Art

[0002] At present, many electronic devices on the market need to switch to battery power supply when the mains power is off, while the traditional power failure detection circuit mostly detects the power failure of one power supply, which has a better effect in a single power supply, and mostly uses the main control circuit to control the battery switching power supply, which consumes a lot of power and has a delay in switching. The utility model can not only independently detect the power failure of two power supplies, but also switch the battery without the main control circuit of the device to ensure that the device can be powered and operated seamlessly when there is no mains power.

[0003] With the development of smart energy meters, the application of smart meters is becoming more and more diversified and complex, and the application of smart meters with auxiliary power supply function is becoming more and more extensive. The utility model mainly solves the problem that the main power supply and auxiliary power supply of the two-way power supply smart meter independently detect power failure and switch to battery power supply in time. Utility Model Content

[0004] The technical problem to be solved by the utility model is generally to provide a power failure detection and battery switching control circuit.

[0005] In order to solve the above problems, the technical solution adopted by the utility model is:

[0006] The utility model aims to provide a power failure detection and battery switching control circuit, which can detect power failure in time through the main power supply and the auxiliary power supply and control the battery switch to open to ensure normal power output.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A power failure detection and battery switching control circuit comprises a main power failure detection circuit, an auxiliary power failure detection circuit, a battery switching control circuit and a battery power supply circuit.

[0009] Furthermore, the input of the main power failure detection circuit VMAIN_IN is electrically connected to resistors R1, R2, and R3, one end of the resistor R3 is connected to GND, and the other end is connected to ZHU_CHECK. Capacitors C1 and C2 are connected in parallel with the resistor R3. The anode of the diode D1 and the cathode of ZHU_CHECK are connected to DVDD.

[0010] Furthermore, the auxiliary power failure detection circuit VMAIN input is connected to resistors R4, R5, and R6, one end of R6 is connected to GND and the other end is connected to FU_CHECK. Capacitors C3 and C4 are connected in parallel with R6. The anode of diode D2 is connected to FU_CHECK and the cathode is connected to DVDD.

[0011] Further, the battery switching control circuit. VMAIN_IN is connected to the anode of diode D5, VMAIN is connected to the anode of diode D6, and VMAIN+ is connected to the cathodes of D3, D5, and D6. The anode of D3 is connected to resistor R7, R7 is connected to Power_Battery_Ctr, and Power_Battery_Ctr is connected to the anode of diode D4 and resistor R8. The cathode of D4 is connected to DVDD and resistor R9. Resistors R8 and R9 are connected to GND.

[0012] Furthermore, the battery power supply circuit battery B1 has a negative electrode connected to GND, a positive electrode connected to a positive electrode of a diode D7, a negative electrode of D7 connected to a capacitor C5 and an input terminal of U1. The output terminal of U1 is connected to a capacitor C6 and a source of a MOS tube Q1, a drain of Q1 is connected to a positive electrode of a dual diode D8, and a negative electrode of D8 is connected to DVDD. The gate of Q1 is connected to a resistor R10, and R10 is connected to Power_Battery_Ctr.

[0013] The utility model has the following beneficial effects:

[0014] 1. The utility model does not need an MCU to control the battery power supply circuit switch. After the two power supplies of the circuit are powered off, they are automatically switched to reduce the power consumption of the circuit.

[0015] 2. The utility model can detect power failure of two power supplies, thus ensuring the reliability of the circuit.

[0016] 3. The main power failure detection circuit, the auxiliary power failure detection circuit and the battery switching control circuit of the utility model are all designed with diodes to prevent the main power detection end, the auxiliary power detection end and the battery switching control output end from overvoltage and damaging the subsequent circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the control circuit of the utility model.

[0018] Figure 2 Main power failure detection circuit diagram.

[0019] Figure 3 This is the auxiliary power failure detection circuit diagram.

[0020] Figure 4 This is the control circuit diagram.

[0021] Figure 5 Circuit diagram for battery powered circuit.

[0022] Label name Label name VMAIN_IN Main power input R1~R10 The first to tenth resistors VMAIN Auxiliary power input C1~C6 The first to sixth resistors ZHU_CHECK Main power detection terminal D1-D8 The first to eighth diodes FU_CHECK Auxiliary power detection terminal B1 Battery VMAIN+ Battery switch control input U1 LDO Power_Battery_Ctr Battery switch control output DVDD Power output 3.3V DETAILED DESCRIPTION

[0023] like Figure 1-5 As shown, the utility model includes a main power failure detection circuit, an auxiliary power failure detection circuit, a battery switching control circuit, and a battery power supply circuit.

[0024] The main power supply power failure detection circuit is used to detect whether the main power supply is powered off.

[0025] The auxiliary power supply power-off detection circuit is used to detect whether the auxiliary power supply is powered off.

[0026] The battery switching circuit is used to control the battery circuit switch.

[0027] The battery power supply circuit is a circuit for supplying power to a load from a battery.

[0028] like Figure 2 The main power supply power-off detection circuit includes resistors R1, R2, R3, capacitors C1, C2, and a diode D1; wherein the main power supply VMAIN_IN input terminal is electrically connected to resistors R1, R2, and R3 in sequence, one end of the resistor R3 is connected to GND, and the other end is connected to the main power supply detection terminal ZHU_CHECK. Capacitors C1 and C2 are connected in parallel with the resistor R3 respectively. The positive electrode of the diode D1 is connected to the main power supply detection terminal, and the negative electrode is connected to DVDD.

[0029] The main power supply input terminal is divided by resistors R1, R2, and R3. The main power supply detection terminal detects the voltage across R3 to determine whether the main power supply is powered off. D1 is used to prevent the voltage at the main power supply detection terminal from being too high to protect the subsequent circuit. C1 and C2 are used for filtering and voltage stabilization.

[0030] like Figure 3 , the auxiliary power supply power-off detection circuit includes resistors R4, R5, R6, capacitors C3, C4, and diode D2;

[0031] The auxiliary power input terminal VMAIN is connected to resistors R4, R5, and R6, one end of the resistor R6 is connected to GND and the other end is connected to the auxiliary power detection terminal FU_CHECK. Capacitors C3 and C4 are connected in parallel with the resistor R6. The positive electrode of the diode D2 is connected to the auxiliary power detection terminal FU_CHECK, and the negative electrode is connected to DVDD.

[0032] Auxiliary power supply power-off detection circuit, the auxiliary power supply input terminal is divided by resistors R4, R5, and R6. The auxiliary power supply detection terminal detects the voltage across R6 to determine whether the main power supply is powered off. D2 is used to prevent the voltage at the main power supply detection terminal from being too high to protect the subsequent circuit. C3 and C4 are used for filtering and voltage stabilization.

[0033] like Figure 4 , the battery switching control circuit includes diodes D3-D6 and resistors R7-R9;

[0034] The main power input terminal VMAIN_IN is electrically connected to the anode of the diode D5, VMAIN is electrically connected to the anode of the diode D6, and VMAIN+ is electrically connected to the cathodes of the diodes D3, D5, and D6; the anode of the diode D3 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to Power_Battery_Ctr, and Power_Battery_Ctr is electrically connected to the anode of the diode D4 and the resistor R8 respectively; the cathode of the diode D4 is connected to DVDD and the resistor R9; and the resistors R8 and R9 are connected to GND respectively.

[0035] like Figure 4 , the main power supply and auxiliary power supply input terminals are input to VMAIN+ through diodes D5 and D6 respectively. Under power supply, VMAIN+ is reverse-conducted by the voltage-stabilizing diode and clamped by diode D4, and Power_Battery_Ctr maintains a voltage value of 4V. Diode D4 ensures that the voltage of Power_Battery_Ctr will not be too high. Resistor R9 ensures that DVDD maintains a stable voltage after power failure. After power failure, Power_Battery_Ctr changes from a high level to a low level.

[0036] like Figure 5 , the battery power supply circuit includes a circuit battery B1, a diode D7, a voltage regulator U1, capacitors C5 and C6, a MOS tube Q1, a dual diode D8 and a resistor R10;

[0037] The negative electrode of the circuit battery B1 is connected to GND and the positive electrode is connected to the positive electrode of the diode D7. The negative electrode of the diode D7 is connected to the capacitor C5 and the input terminal pin 1 of the voltage regulator U1. The pin 2 of the voltage regulator U1 is grounded. The output terminal pin 3 of the voltage regulator U1 is connected to the capacitor C6 and the source of the MOS tube Q1. The drain of the MOS tube Q1 is connected to the positive electrode of the dual diode D8. The negative electrode of the dual diode D8 is connected to DVDD. The gate of the MOS tube Q1 is connected to the resistor R10, and R10 is connected to the battery switching control output terminal through Power_Battery_Ctr.

[0038] like Figure 5 , battery power supply circuit, the battery voltage is protected by diode D7 and then stepped down by LDO to output voltage. When Power_Battery_Ctr has power, the drain and source of PMOS are controlled to be non-conductive and the battery circuit does not work. After the main power supply and auxiliary power supply are powered off, Power_Battery_Ctr is at a low level. At this time, the drain and source of PMOS are conductive, and the voltage output by U1 is converted to DVDD through diode D8 to power the load.

[0039] In the utility model, the main power failure detection circuit and the auxiliary power failure detection circuit can independently detect whether the mains power is off, and switch to battery power supply after both power supplies are off. There is no need to control the battery power supply circuit switch to open through the MCU, and the battery power supply is automatically switched after both power supplies are off, thereby reducing the power consumption of the circuit. The main power failure detection circuit, the auxiliary power failure detection circuit, and the battery switching control circuit are all designed with diodes to prevent the main power detection terminal, the auxiliary power detection terminal, and the battery switching control output terminal from overvoltage and damaging the subsequent circuit.

[0040] The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0041] 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. Power failure detection and battery switching control circuit, characterized in that: It includes a main power failure detection circuit, an auxiliary power failure detection circuit, a battery switching control circuit and a battery power supply circuit; wherein, A main power failure detection circuit is used to detect whether the main power failure occurs; Auxiliary power supply power failure detection circuit, used to detect whether the auxiliary power supply is powered off; A battery switching circuit, used to control the battery circuit switch; The battery power supply circuit is a circuit for supplying power to a load from a battery; The main power supply power-off detection circuit and the auxiliary power supply power-off detection circuit are electrically connected to the input end of the battery switching control circuit respectively; the output end of the battery switching control circuit is electrically connected to the input end of the battery power supply circuit.

2. The power failure detection and battery switching control circuit according to claim 1, characterized in that: The main power failure detection circuit includes resistors R1, R2, R3, capacitors C1, C2, and a diode D1; wherein, The input terminal of the main power supply VMAIN_IN is electrically connected to resistors R1, R2, and R3 in sequence; One end of the resistor R3 is connected to GND, and the other end is connected to the main power supply detection terminal ZHU_CHECK; capacitors C1 and C2 are respectively connected in parallel with the resistor R3; The anode of diode D1 is connected to the main power supply detection terminal ZHU_CHECK, and the cathode is connected to DVDD.

3. The power failure detection and battery switching control circuit according to claim 2, characterized in that: The auxiliary power failure detection circuit includes resistors R4, R5, R6, capacitors C3, C4, and a diode D2; The auxiliary power input terminal VMAIN is electrically connected to resistors R4, R5, and R6, one end of the resistor R6 is connected to GND and the other end is connected to the auxiliary power detection terminal FU_CHECK; capacitors C3 and C4 are connected in parallel with the resistor R6; the positive electrode of the diode D2 is connected to the auxiliary power detection terminal FU_CHECK, and the negative electrode is connected to DVDD.

4. The power failure detection and battery switching control circuit according to claim 3, characterized in that: The battery switching control circuit includes diodes D3-D6 and resistors R7-R9; The main power input terminal VMAIN_IN is electrically connected to the anode of the diode D5, VMAIN is electrically connected to the anode of the diode D6, and VMAIN+ is electrically connected to the cathodes of the diodes D3, D5, and D6; the anode of the diode D3 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to Power_Battery_Ctr, and Power_Battery_Ctr is electrically connected to the anode of the diode D4 and the resistor R8 respectively; the cathode of the diode D4 is connected to DVDD and the resistor R9; and the resistors R8 and R9 are connected to GND respectively.

5. The power failure detection and battery switching control circuit according to claim 4, characterized in that: The battery power supply circuit includes a circuit battery B1, a diode D7, a voltage regulator U1, capacitors C5 and C6, a MOS tube Q1, a dual diode D8 and a resistor R10; The negative electrode of the circuit battery B1 is connected to GND and the positive electrode is connected to the positive electrode of the diode D7. The negative electrode of the diode D7 is connected to the capacitor C5 and the input pin 1 of the voltage regulator U1 respectively. The pin 2 of the voltage regulator U1 is grounded. The output pin 3 of the voltage regulator U1 is connected to the capacitor C6 and the source of the MOS tube Q1 respectively. The drain of the MOS tube Q1 is connected to the positive electrode of the dual diode D8, and the negative electrode of the dual diode D8 is connected to DVDD. The gate of the MOS tube Q1 is connected to the resistor R10, and R10 is connected to the battery switching control output terminal through Power_Battery_Ctr.

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