Multi-mode battery switching circuit

Abstract

The utility model relates to a multi-mode battery switching circuit, which comprises capacitors CV1, CV2 and CV3, NMOS (N-channel Metal Oxide Semiconductor) tubes QV1 and QV2, a Schottky switch tube DV1, resistors RV1, RV2, RV3, RV4, RV5 and RV6, a voltage stabilizer DV2 and a voltage detection chip UV1, in the voltage detection chip UV1, a pin 2 is divided into two paths, one path is connected to a super capacitor end V-CAP, and the other path is grounded through a capacitor CV3; pins 3-5 are grounded; the pin 1 is divided into three paths, one path is connected with a super capacitor end V-CAP through a resistor RV6, the second path is grounded through a resistor RV5, and the third path is connected with a grid electrode of an NMOS tube QV2; the source electrode of the NMOS tube QV2 is connected with built-in battery voltage BV + 16V through a Schottky switch tube DV1, and the drain electrode of the NMOS tube QV2 is connected with the source electrode of the NMOS tube QV1. The device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to a multi-mode battery switching circuit. Background Art

[0002] The international smart meter industry requires that the service life of the entire meter should be no less than 10 years, which is a huge challenge to the power consumption of the built-in battery of the meter. In some applications, special requirements such as 7 or 14 days of LCD display are required, which will undoubtedly greatly increase the power consumption of the built-in battery and shorten the service life.

[0003] In order to solve the problem that the service life of the built-in battery of the whole meter is not less than 10 years, the solution usually used is to add a supercapacitor for power supply or an additional battery or other reserve power supply. The applicant found that the problem that comes with the proposal of the solution is how to realize the intelligent multi-mode battery switching when there is external AC power supply, supercapacitor (extra battery or energy storage power supply) and built-in battery, that is, to realize the three power priorities of the multi-mode battery switching circuit, in order, the external power supply has the highest priority, the supercapacitor (extra battery or energy storage power supply) is second, and the built-in battery is the lowest. Currently, there are mainly two ideas for realizing multi-mode battery switching: using software detection and control solutions, using MCU to intermittently detect the status of each power supply to realize the judgment and switching, but this method has the problem of untimely detection, resulting in the inability to achieve seamless switching; using discrete complex hardware logic control solutions, but this method has the disadvantages of high power consumption, low control voltage accuracy, and difficulty in maintenance; Utility Model Content

[0004] The technical problem to be solved by the utility model is generally to provide a multi-mode battery switching circuit, which can realize the multi-mode battery switching circuit to ensure seamless power switching and has the advantages of simple control, high control accuracy, low cost, etc.

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

[0006] A multi-mode battery switching circuit includes capacitors CV1, CV2 and CV3, NMOS tubes QV1, QV2, Schottky switch tube DV1, resistors RV1, RV2, RV3, RV4, RV5, RV6, a voltage regulator DV2, and a voltage detection chip UV1;

[0007] In the voltage detection chip UV1, pin 2 is divided into two paths, one path is connected to the super capacitor terminal V-CAP, and the other path is grounded through capacitor CV3; pins 3-5 are all grounded; pin 1 is divided into three paths, one path is connected to the super capacitor terminal V-CAP through resistor RV6, the second path is grounded through resistor RV5, and the third path is connected to the gate of NMOS tube QV2; the source of NMOS tube QV2 is connected to the built-in battery voltage BV+16V through Schottky switch tube DV1, and the drain of NMOS tube QV2 is connected to the source of NMOS tube QV1;

[0008] The built-in battery voltage BV+16V is connected to Battery1-ADC through resistor RV1; Battery1-ADC is connected to ground and resistor RV4 through capacitor CV2;

[0009] The resistor RV4 is divided into two paths, one path is grounded, and the other path is connected to the resistor RV2; one path of the output end of the resistor RV2 is grounded through the capacitor CV1, and the other path is connected to the gate of the NMOS tube QV1 and the resistor RV3;

[0010] The drain of the NMOS tube QV1 is connected to MVDD, and the resistor RV3 is connected to the external AC power supply MHVDD through the voltage regulator device DV2.

[0011] As a further improvement of the above technical solution:

[0012] Battery1-ADC is connected to the built-in battery.

[0013] Capacitors CV1, CV2 and CV3 are ceramic capacitors.

[0014] The multi-mode battery switching circuit has the following working switching states:

[0015] Switching state 1: the smart meter is powered by external AC power, and the supercapacitor and built-in battery are in the same state;

[0016] Switching state 2: the smart meter is powered by external AC power and built-in battery at the same time;

[0017] Switching state three: the supercapacitor and the built-in battery exist at the same time.

[0018] In switching state one,

[0019] The external AC power supply MHVDD supplies power to MVDD, the NMOS tube QV1 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD;

[0020] When the supercapacitor terminal V_CAP is greater than the set voltage, the NMOS tube QV2 is cut off; the built-in battery voltage BV+3.6V stops supplying power to MVDD;

[0021] Battery_1_ADC is used to connect to MCU to detect battery power;

[0022] When the voltage of the external AC power supply MHVDD is removed, the NMOS tubes QV2 and QV1 are in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD;

[0023] When the external AC power supply MHVDD is in the power removal state, the supercapacitor terminal V_CAP is lower than the set threshold, the GS voltage of the NMOS tube QV2 reaches the turn-on voltage state, and the NMOS tubes QV1 and QV2 are in the on state; the built-in battery voltage BV+3.6V is in the power supply state to MVDD, achieving the purpose of battery last use switching.

[0024] In switching state two, when the external AC power supply MHVDD is in the power supply state, the NMOS tube QV1 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD; the NMOS tube QV2 is always in the on state; when the external AC power supply MHVDD is in the power-off state, the NMOS tube QV2 is in the on state, and the built-in battery BV+3.6V switches to the external AC power supply MVDD output, thereby achieving the final use switching purpose of the battery.

[0025] In the switching state three, when the external AC power supply HVDD is in the power-off state, the G-level voltage of the NMOS tube QV1 is at a low level;

[0026] When the supercapacitor V_CAP is greater than the set value, the S-level voltage of the NMOS tube QV2 is less than the set value; the NMOS tube QV2 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD

[0027] When the supercapacitor V_CAP is less than the preset value, the G-level voltage of the NMOS tube QV2 is at a low level, the voltage of the built-in battery BV+3.6V is greater than the G turn-on voltage of the NMOS tube QV2, the NMOS tube QV2 is turned on, and the built-in battery BV+3.6V is switched to the external AC power supply MVDD output, achieving the purpose of battery last use switching.

[0028] The utility model has the following advantages: 1. It uses hardware control to achieve seamless power switching, has good anti-interference and reliable logic control. 2. It uses two NMOS tubes in series to achieve switching of three different power priorities, and increasing the number of series stages can achieve more priority switching methods for different power supplies. 3. The external power input range is wide. By adjusting the voltage regulation value of DV2 and the resistance value of RV2 and RV3, the MHVDD input range can be expanded within a certain range, which has high flexibility. 4. High detection accuracy. The voltage detection chip of UV1 can achieve high-precision 1% voltage detection control, thereby maximizing the use of V_CAP power energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a multi-mode battery switching circuit of the utility model. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, the multi-mode battery switching circuit of this embodiment is essentially that when external AC power supply, super capacitor (extra battery or energy storage power supply) and built-in battery power supply exist at the same time or at different times, the power supply priority is from high to low: external AC power supply, super capacitor (extra battery or energy storage power supply), and built-in battery. In this way, in different modes, the battery power is used last to ensure long life. The utility model of this circuit is applied to the field of smart meters. The circuit of this utility model Figure 1 As shown below,

[0031] The multi-mode battery switching circuit is composed of the following components: CV1, CV2 and CV3 are ceramic capacitors, which provide energy storage filtering for the circuit; QV1 and QV2 are NMOS tubes, which act as switches in the circuit; DV1 is a Schottky switch tube, which acts as an anti-reverse function in the circuit; RV1, RV2, RV3, RV4, RV5 and RV6 are resistors, which act as current limiting and voltage dividing functions in the circuit; DV2 is a voltage stabilizing device, which acts as a voltage stabilizing device in the circuit; UV1 is a voltage detection chip, which acts as a high-precision voltage detection chip in the circuit;

[0032] The working process of the multi-mode battery switching circuit can be divided into the following situations:

[0033] S1. When the smart meter is powered by external AC power, and supercapacitors (extra batteries or energy storage power supplies) and built-in batteries exist at the same time, the switching is as follows:

[0034] S1-1 and MHVDD are powered by external AC power. After being stabilized at 6.8V by DV2, the remaining voltage is divided by the voltage-dividing resistors RV3 and RV2 to about 4V. The S-level voltage of QV1 is less than 4V, so QV1 cannot be turned on. BV+3.6V cannot supply power to MVDD.

[0035] S1-2, V_CAP is a supercapacitor (extra battery or energy storage power source). When V_CAP is greater than 3.2V, the voltage detection chip UV1 detects it and is divided by RV5 and RV6 to a voltage close to V_CAP. The S-level voltage of QV2 is less than 3.2V, so it is not turned on. BV+3.6V cannot supply power to MVDD.

[0036] S1-3, BV+3.6V is the built-in battery voltage, and the fully charged battery voltage is about 3.65V; RV1 and RV4 divide the built-in battery voltage, and Battery_1_ADC is connected to the MCU to detect the battery power;

[0037] S1-4, when the external AC power supply of MHVDD is removed, but because the voltage of V_CAP is greater than 3.2V, QV2 is not conducting, QV1 is not conducting; BV+3.6V cannot supply power to MVDD;

[0038] S1-5. When the external AC power supply of MHVDD is removed, V_CAP is lower than 3.2V or removed, the GS voltage of QV2 reaches the turn-on voltage, QV2 is turned on, and similarly QV1 is turned on; at this time, BV+3.6V supplies power to MVDD, achieving the final use switching purpose of the battery.

[0039] S2. When the smart meter is powered by external AC power and built-in battery at the same time, the switch is as follows:

[0040] S2-1 and MHVDD are powered by external AC power. After being stabilized at 6.8V by DV2, the remaining voltage is divided by the voltage-dividing resistors RV3 and RV2 to about 4V. The S-level voltage of QV1 is less than 4V, so QV1 cannot be turned on. BV+3.6V cannot supply power to MVDD.

[0041] S2-2, because V_CAP has no voltage, the output is pulled to a low level by the voltage divider resistor RV5, causing QV2 to be turned on all the time;

[0042] S2-3, after MHVDD is powered off by external AC power, QV1 is directly turned on. Since QV2 is turned on, the built-in battery switches to MVDD output, achieving the purpose of battery last use switching.

[0043] S3: When both supercapacitor (extra battery or energy storage power source) and built-in battery exist, the switch is as follows:

[0044] S3-1, MHVDD has no external AC power supply, and the G-level voltage of QV1 is pulled down to a low level by resistor RV2. Whether QV1 is turned on or not depends on the voltage of the S-level of QV1;

[0045] S3-2, V_CAP is a supercapacitor (extra battery or energy storage power source). When V_CAP is greater than 3.2V, the voltage detection chip UV1 detects it and is divided by RV5 and RV6 to a voltage close to V_CAP. The S-level voltage of QV2 is less than 3.2V, so it is not turned on. BV+3.6V cannot supply power to MVDD.

[0046] S3-3, when V_CAP is a supercapacitor (extra battery or energy storage power source) less than 3.2V or removed, the G level voltage of QV2 is pulled down to a low level by RV2, the voltage of the built-in battery is greater than the G turn-on voltage of QV2, QV2 is turned on, and the built-in battery switches to MVDD output, achieving the purpose of switching the battery for the last use.

[0047] In summary, in the three different modes of S1, S2, and S3, the built-in battery can be switched to power supply with the lowest priority.

[0048] When this circuit realizes multi-mode power supply, the priority is the external power supply with the highest priority, the super capacitor (extra battery or energy storage power supply) is the second, and the built-in 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 used, the priority power supply of each power supply is realized by controlling the on and off of the NMOS tubes QV1 and QV2. Among them, the external AC power supply circuit control mode; through the series connection of the voltage regulator tube DV2, the design of resistors RV2 and RV3 realizes the G-level control of the NMOS tube QV1, and realizes the conduction control of QV1; secondly, the super capacitor (extra battery or energy storage power supply) power supply circuit control mode; through the external precision voltage detection chip UV1, the design of resistors RV5 and RV6 realizes the G-level control of the NMOS tube QV2, and realizes the conduction control of QV2; thirdly: QV1 and QV2 series control mode; the control of this circuit adopts the series connection of QV1 and QV2 to realize the priority switching sequence of the three power supplies. Fourth: Any multiple NMOS tube series connection derived from the series connection of QV1 and QV2 can realize more mode priority control methods.

[0049] The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0050] 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 multi-mode battery switching circuit, characterized in that: Including capacitors CV1, CV2 and CV3, NMOS tubes QV1, QV2, Schottky switch tube DV1, resistors RV1, RV2, RV3, RV4, RV5, RV6, voltage regulator DV2, voltage detection chip UV1; In the voltage detection chip UV1, pin 2 is divided into two paths, one path is connected to the super capacitor terminal V-CAP, and the other path is grounded through capacitor CV3; pins 3-5 are all grounded; pin 1 is divided into three paths, one path is connected to the super capacitor terminal V-CAP through resistor RV6, the second path is grounded through resistor RV5, and the third path is connected to the gate of NMOS tube QV2; the source of NMOS tube QV2 is connected to the built-in battery voltage BV+16V through Schottky switch tube DV1, and the drain of NMOS tube QV2 is connected to the source of NMOS tube QV1; The built-in battery voltage BV+16V is connected to Battery1-ADC through resistor RV1; Battery1-ADC is connected to ground and resistor RV4 through capacitor CV2; The resistor RV4 is divided into two paths, one path is grounded, and the other path is connected to the resistor RV2; one path of the output end of the resistor RV2 is grounded through the capacitor CV1, and the other path is connected to the gate of the NMOS tube QV1 and the resistor RV3; The drain of the NMOS tube QV1 is connected to MVDD, and the resistor RV3 is connected to the external AC power supply MHVDD through the voltage regulator device DV2.

2. The multi-mode battery switching circuit according to claim 1, characterized in that: Battery1-ADC is connected to the built-in battery.

3. The multi-mode battery switching circuit according to claim 1, characterized in that: Capacitors CV1, CV2 and CV3 are ceramic capacitors.

4. The multi-mode battery switching circuit according to claim 2, characterized in that: The multi-mode battery switching circuit has the following working switching states: Switching state 1: the smart meter is powered by external AC power, and the supercapacitor and built-in battery are in the same state; Switching state 2: the smart meter is powered by external AC power and built-in battery at the same time; Switching state three: the supercapacitor and the built-in battery exist at the same time.

5. The multi-mode battery switching circuit according to claim 4, characterized in that: In switching state 1, The external AC power supply MHVDD supplies power to MVDD, the NMOS tube QV1 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD; When the supercapacitor terminal V_CAP is greater than the set voltage, the NMOS tube QV2 is cut off; the built-in battery voltage BV+3.6V stops supplying power to MVDD; Battery_1_ADC is used to connect to MCU to detect battery power; When the voltage of the external AC power supply MHVDD is removed, the NMOS tubes QV2 and QV1 are in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD; When the external AC power supply MHVDD is in the power removal state, the supercapacitor terminal V_CAP is lower than the set threshold, the GS voltage of the NMOS tube QV2 reaches the turn-on voltage state, and the NMOS tubes QV1 and QV2 are in the on state; the built-in battery voltage BV+3.6V is in the power supply state to MVDD, achieving the purpose of battery last use switching.

6. The multi-mode battery switching circuit according to claim 5, characterized in that: In switching state two, when the external AC power supply MHVDD is in the power supply state, the NMOS tube QV1 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD; the NMOS tube QV2 is always in the on state; when the external AC power supply MHVDD is in the power-off state, the NMOS tube QV2 is in the on state, and the built-in battery BV+3.6V switches to the external AC power supply MVDD output, thereby achieving the final use switching purpose of the battery.

7. The multi-mode battery switching circuit according to claim 6, characterized in that: In the switching state three, when the external AC power supply HVDD is in the power-off state, the G-level voltage of the NMOS tube QV1 is at a low level; When the supercapacitor V_CAP is greater than the set value, the S-level voltage of the NMOS tube QV2 is less than the set value; the NMOS tube QV2 is in the cut-off state, and the built-in battery voltage BV+3.6V stops supplying power to MVDD; When the supercapacitor V_CAP is less than the preset value, the G-level voltage of the NMOS tube QV2 is at a low level, the voltage of the built-in battery BV+3.6V is greater than the G turn-on voltage of the NMOS tube QV2, the NMOS tube QV2 is turned on, and the built-in battery BV+3.6V is switched to the external AC power supply MVDD output, achieving the purpose of battery last use switching.

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