CN104821653A - Ammeter and power supply circuit therein, and power supply control method inside the ammeter - Google Patents

Abstract

The embodiment of the present invention designs an electric meter, which includes functional devices and a power supply priority control circuit coupled to it through a power line. It includes a first power supply, and the AC voltage part of the power supply Perform A/D conversion, and convert it into a first direct current voltage through an electrically coupled DC/DC converter, and supply a part of the ammeter function device to work; control the first switch of the first power supply and the ammeter function device on and off; the second Two power supplies, used to directly provide DC voltage for another part of the ammeter function device; a second switch for controlling the on-off of the second power supply and the ammeter function device; and a voltage limiter connected between the first switch and the second switch The device is used to control the corresponding on-off sequence of the second switch through the on-off of the first switch. The invention also discloses a power supply circuit inside the electric meter and a power supply control method inside the electric meter.

Description

Electric meter and its internal power supply circuit, power supply control method inside the electric meter

technical field

Embodiments of the present invention mainly relate to grid power control technology, and more specifically, relate to an electric meter and a power supply control circuit thereof.

Background technique

Electric measuring equipment, especially some functional board components in the electric meter or distribution transformer acquisition terminal need to be powered by batteries. For example, in the three-phase smart meter, there are two kinds of batteries designed, one is the clock battery, and the other is the stop reading Batteries, these two batteries play a very important role in data storage and fee settlement of three-phase smart meters. If the power consumption of the battery is too large in practical applications, it will seriously affect the service life of the battery and reduce the safety of the electric energy meter. In order to better realize battery switching and reduce battery loss, a battery switching circuit based on P-MOS technology is proposed.

Contents of the invention

The invention utilizes P-channel MOSFETs to build a power switching circuit, reduces loss, can well realize power switching, and reduces energy consumption. In a preferred embodiment, a multi-channel power supply control circuit is designed to select and control at least one power supply to supply power to functional devices, including: a first switch arranged between the at least one power supply and the functional device, used for power supply Select; connect the second switch of the first switch, perform closing or opening action according to the first switch, and further connect the at least one power supply to form a closed loop; and set in the closed loop The voltage limiting device is used to control the on-off sequence between the second switches.

In one embodiment, it further includes: an alternating voltage step-down circuit connected between the at least one power supply and the first switch, for performing A/D conversion on the AC voltage part in the power supply, and passing through a power supply The coupled DC/DC converter converts the first direct current voltage to work for some functional devices.

In one embodiment, the first direct current voltage is configured to control the first switch to be turned on or off, so as to be further converted into a second direct current voltage by the first switch for the operation of another part of functional devices.

In one embodiment, the second direct current voltage is used by the voltage limiting device to inhibit the closing of the second switch, thereby inhibiting other remaining power sources from supplying power to the functional devices.

In one embodiment, the voltage limiting device is a TTL transistor.

In one embodiment, a forward conduction switch is provided between the first switch and the functional device, which outputs the first DC voltage to the functional device and suppresses DC voltages from other remaining power sources.

In one embodiment, a second switch is configured for every other remaining power source.

In another embodiment, the integrated power control board in the ammeter is coupled to the function board of the ammeter through a power cord, and the integrated power control board includes a plurality of power supplies for supplying power to the function board, which further It includes: a first switch arranged between the multiple power supplies and the function board, used to select one of the multiple power supplies; a second switch connected to the first switch, according to the first switch to perform a closing or opening action, and further connect the at least one power supply to form a closed loop; and a voltage limiting device arranged in the closed loop is used to control the on-off sequence between the second switches, Wherein the first switch or the second switch is respectively connected to a DC/DC converter to convert to the working voltage required by the function board.

In one embodiment, the second switch is a voltage-suppressed transistor array controlled by a voltage signal change from the voltage limiting device.

In one embodiment, the alternating step-down circuit connected between the power supply and the first switch is used to perform A/D conversion on the AC voltage in the power supply, and through the DC/DC converter converted into the first DC voltage for the function board to work. In one embodiment, a forward conduction switch is provided between the first switch and the functional board, which outputs the first DC voltage to the functional board and suppresses DC voltages from other remaining power sources.

In one embodiment, when the first switch is turned off, the forward conduction switch conducts another remaining power supply for some function boards to work.

In one embodiment, when one of the second switches is turned off, the forward conduction switch turns on another remaining power supply for another part of the function board to work.

In one embodiment, a second switch is configured for every other remaining power source.

In another embodiment, an electric meter is designed, including functional devices, and a power supply priority control circuit coupled to it through a power line, which includes a first power supply, and converts the alternating current in the power supply to The voltage part performs A/D conversion, and converts it into a first direct current voltage through an electrically coupled DC/DC converter, and supplies a part of the electric meter function device to work; the first switch that controls the on-off of the first power supply and the electric meter function device The second power supply is used to directly provide DC voltage for another part of the ammeter function device; the second switch for controlling the on-off of the second power supply and the ammeter function device; and the switch connected between the first switch and the second switch The voltage limiting device is used to control the corresponding on-off sequence of the second switch through the on-off of the first switch. In one embodiment, the first switch and the second switch are respectively connected to a DC/DC converter to convert to the working voltage required by the functional device.

In one embodiment, a forward conduction switch is provided between the DC/DC converter and the functional device, and only outputs a DC voltage to the functional device, and suppresses DC voltages from other remaining power sources.

In one embodiment, the first switch or voltage limiting device is a TTL transistor.

In one embodiment, the second switch is a voltage-suppressed transistor array, which/they are controlled by a voltage signal change from the voltage limiting device.

In one embodiment, the functional device includes an on-chip single-chip microcomputer, the port PWR_CH of which is connected to a voltage limiting device, and when the voltage limiting device is turned on, the single-chip microcomputer is controlled not to receive the DC voltage from the first power supply.

The technical effect of the present invention is obvious, the power switching circuit is built by P-channel MOSFET, the loss is reduced, the power switching can be well realized, the power supply can be separated according to the needs of the functional circuit board of the electric meter, the battery power can be well utilized, and the electric measurement can be reduced. Equipment disassembly and maintenance costs.

Description of drawings

FIG. 1 is a partial schematic block diagram of a power supply control circuit according to an embodiment of the present invention.

Detailed ways

Referring to FIG. 1 , it schematically shows a multi-channel power supply control circuit in a three-phase electric meter, which is used to select and control multiple power supplies to supply power to functional devices in the electric meter, including setting between the at least one power supply and the functional devices The first switch, preferably a triode D5 and a triode D6 electrically connected to it, is used to select the power source, for example, when the AC power source is obtained from the outside, it is transformed into a large DC current through the current-voltage conversion CT and the internal energy storage circuit Select between the provided DC current; connect the second switch Q1 and Q2 of the first switch D5, perform closing or opening action according to the first switch D5 and D6, and further connect multiple power sources to form a a closed loop; and a voltage limiting device arranged in the closed loop, for controlling the on-off sequence of the first switch and the second switch, or between the second switches.

In one embodiment, the power supply further includes an alternating step-down circuit connected between the power supply and the first switch Q5, such as a common CT-type step-down circuit or a resistance-capacitance step-down circuit, which converts the AC voltage in the 220V AC power supply to The voltage part performs A/D conversion, and is converted into a first DC voltage, such as +4V, by an electrically coupled DC/DC converter U1, for some functional devices to work.

In one embodiment, the first direct current voltage is configured to control the first switch to be turned on or off, so as to be further converted into a second direct current voltage by the first switch for the operation of another part of functional devices.

In one embodiment, the second direct current voltage is used by the voltage limiting device to inhibit the closing of the second switch, thereby inhibiting other remaining power sources from supplying power to the functional devices.

In one embodiment, the voltage limiting device selects D6, which can be used as a TTL transistor switch or a switch with a voltage limiting function. As shown in the figure, when there is an AC signal in the AC power source MP_IN, the transistor D5 is turned on , so that the +4V DC voltage is obtained through the DC/DC converter U1 for use by functional devices, and at the same time the transistor D6 is turned off, and the cut-off action then affects the turn-off of the second switch Q1 and Q2 at the rear end, so that there is only one DC power supply Supply the VCC terminal to output to functional devices. In one embodiment, forward conduction switches (bidirectional switches D1, D2 as shown in the figure) are provided between the first switch D5 and the functional device, and the first DC voltage output to the functional device +4V , the DC voltage from other remaining power supply parts BAT1, BAT2 is suppressed. Since the MOS arrays Q1 and Q2 are turned off, there will still be a small current flowing out, so the cut-off switch D2 is set to prevent this part of the current from flowing into the VCC terminal, and at the same time further save power.

In the illustrated embodiment, a second switch Q1 and Q2 is respectively configured for each of the remaining power sources BAT1 and BAT2.

In one embodiment, there are three power sources in the three-phase electric meter, which are AC rectified step-down power supply, battery power supply BAT2 for stop reading, and clock battery power supply BAT1, and their power supply priorities are set to decrease in order.

When there is AC power on the external power line connected to the terminal of the ammeter, the ammeter uses, for example, DC/DC to reduce the first power supply of +4V output by the chip, and uses this +4V power supply as a signal to turn on the NPN transistor D5, because D5 is turned on Grounding makes the triode D6 cut off and output +3.3V high level. Since the P-MOS transistor Q1 is a voltage control transistor, when its V _gs voltage is higher than 1.8V, the transistor is cut off, so the high level output by the triode D6 is used to The two P-MOSs of Q1 and Q2 of the cut-off control battery BAT2 and the clock battery BAT1 are directly powered by the +4V first power supply through the diode D1 at this time, and these two batteries do not supply power to the outside.

In another embodiment, an integrated power control board in an ammeter is designed, which is coupled to the function board of the ammeter through a power cord, and the integrated power control board includes 3 power supplies for supplying power to the function board, which is further It includes: a first switch D5 arranged between the multiple power supplies and the function board, for selecting one of the multiple power supplies; the second switches Q1, Q2 connected to the first switch D5, according to The first switch D5 is used to close or break, and further connect the at least one power source to form a closed loop; and a voltage limiting device arranged in the closed loop is used to control the The on-off sequence between them, wherein the first switch or the second switch is respectively connected to a DC/DC converter to convert to the working voltage required by the function board.

In one embodiment, the second switch is a voltage-suppressed transistor array controlled by a voltage signal change from the voltage limiting device.

In one embodiment, the alternating step-down circuit connected between the power supply and the first switch is used to perform A/D conversion on the AC voltage in the power supply, and through the DC/DC converter converted into the first DC voltage for the function board to work. In one embodiment, a forward conduction switch is provided between the first switch and the functional board, which outputs the first DC voltage to the functional board and suppresses DC voltages from other remaining power sources.

In one embodiment, when the first switch is turned off, the forward conduction switch conducts another remaining power supply for some function boards to work.

In one embodiment, when one of the second switches is turned off, the forward conduction switch turns on another remaining power supply for another part of the function board to work.

In one embodiment, a second switch is configured for every other remaining power source.

In another embodiment, an electric meter is designed, including functional devices, and a power supply priority control circuit coupled to it through a power line, which includes a first power supply, and converts the alternating current in the power supply to The voltage part performs A/D conversion, and converts it into a first direct current voltage through an electrically coupled DC/DC converter, and supplies a part of the electric meter function device to work; the first switch that controls the on-off of the first power supply and the electric meter function device The second power supply is used to directly provide DC voltage for another part of the ammeter function device; the second switch for controlling the on-off of the second power supply and the ammeter function device; and the switch connected between the first switch and the second switch The voltage limiting device is used to control the corresponding on-off sequence of the second switch through the on-off of the first switch. In one embodiment, the first switch and the second switch are respectively connected to a DC/DC converter to convert to the working voltage required by the functional device.

In one embodiment, a forward conduction switch is provided between the DC/DC converter and the functional device, and only outputs a DC voltage to the functional device, and suppresses DC voltages from other remaining power sources.

In one embodiment, the first switch or voltage limiting device is a TTL transistor.

In one embodiment, the second switch is a voltage-suppressed transistor array, which/they are controlled by a voltage signal change from the voltage limiting device.

In one embodiment, the on-chip functional device includes an on-chip single-chip microcomputer, and its port PWR_CH is connected to a voltage limiting device, and when the voltage limiting device D6 is turned on, the single-chip microcomputer is controlled not to receive +4V DC voltage from the first power supply, and Select the remaining DC voltages BAT1, BAT2.

In another embodiment, a power supply circuit inside the ammeter is designed, including N-level power supply units cascaded with each other, each power supply unit includes a number of first power supplies, and the power supply in the power supply is converted by its alternating step-down circuit A/D conversion is carried out on the AC voltage part, and converted into the first DC voltage through an electrically coupled DC/DC converter, which is used to work for some functional devices of the ammeter; A switch; a plurality of second power supplies, used to directly provide DC voltage for another part of the ammeter function device; a second switch that controls the on-off of each second power supply and the ammeter function device; and is connected to the first switch and the second The voltage limiting device between the switches is used to control the corresponding on-off sequence of the second switch through the on-off of the first switch.

In one embodiment, the functional device of the ammeter includes a plurality of expandable external ports, and each expandable port is connected to a power supply unit, wherein the power supply sequence between each power supply unit and the previous cascaded power supply units is gradually reduced of.

In one embodiment, the power supply circuit further includes a hardware state machine connected to the plurality of expandable external ports, which is used to determine the magnitude of the logic level between the two power supply units according to the sequence of required power supply, so as to Select a different power supply unit. In another embodiment, a power supply control method inside an electric meter is designed, comprising the steps of: setting a plurality of power supply lines in the electric meter, and each power supply line is connected to a power supply priority control circuit; The AC step-down circuit performs A/D conversion on the AC voltage part of the power supply, and converts it into a first DC voltage through an electrically coupled DC/DC converter, which is used for some functional devices of the ammeter; through the power supply priority The first switch in the control circuit controls the on-off between the first power supply and the electric meter function device; through the second power supply of the power supply priority control circuit, directly provides DC voltage for another part of the electric meter function device; through the power supply priority control circuit The second switch controls the on-off of the second power supply and the meter function device; and controls the on-off of the second switch relative to the first switch through a voltage limiting device connected between the first switch and the second switch break sequence.

In one embodiment, it further includes the step of cascading multiple power supply priority control circuits.

In one embodiment, when the external power line of the ammeter has no alternating current, the DC/DC converter U1 does not work, the triode D5 is turned off, and the triode D6 is turned on to output a low level. At this time, the gate of the transistor Q1 that controls the stop reading of the battery BAT2 is activated. Set to low level, so the transistor Q1 is turned on, and the battery BAT2 supplies power to VCC through the DC/DC converter chip U1.

Only when there is no external AC power and the battery BAT2 is stopped, can the clock battery BAT1 power be turned on. At this time, the single-chip microcomputer has entered the sleep mode, so the battery power consumption can be controlled at about 1uA, thereby ensuring the working life of the clock battery for 10 years.

Claims (10)

1. The electric meter is characterized in that: it includes a functional device, and a power supply priority control circuit coupled with it through a power line, it includes a first power supply, and the AC voltage part in the power supply is carried out by its alternating step-down circuit A/D conversion, and converted into a first DC voltage through an electrically coupled DC/DC converter, for a part of the ammeter function device to work; the first switch that controls the on-off of the first power supply and the ammeter function device; the second A power supply, used to directly provide DC voltage to another part of the ammeter function device; a second switch for controlling the on-off of the second power supply and the ammeter function device; and a voltage limiting device connected between the first switch and the second switch , used to control the corresponding on-off sequence of the second switch through the on-off of the first switch. 2. The electricity meter according to claim 1, characterized in that: the first switch and the second switch are respectively connected to a DC/DC converter to convert to the working voltage required by the functional device, wherein in the A forward conduction switch is arranged between the DC/DC converter and the functional device, and only outputs a DC voltage to the functional device, and suppresses DC voltages from other remaining power sources. 3. The electric meter according to claim 1, characterized in that: the first switch or voltage limiting device is a TTL transistor. 4. The electricity meter according to claim 1, characterized in that: the second switch is a voltage-suppressed transistor array, which/they are controlled by a voltage signal change from the voltage limiting device. 5. The electric meter according to claim 1, characterized in that: the functional device includes an on-chip single-chip microcomputer, and its port PWR_CH is connected to a voltage limiting device, and when the voltage limiting device is turned on, the single-chip microcomputer is controlled not to receive power from the first power supply. of DC voltage. 6. A power supply control method inside the ammeter, characterized in that it comprises the steps of: setting a plurality of power supply lines in the ammeter, each power supply line is connected to a power supply priority control circuit; through the alternating drop in the power supply priority control circuit The voltage circuit performs A/D conversion on the AC voltage part in the power supply, and converts it into a first DC voltage through an electrically coupled DC/DC converter, which is used for a part of the electric meter function device to work; through the power supply priority control circuit The first switch of the first switch controls the on-off between the first power supply and the functional device of the meter; the second power supply of the power supply priority control circuit directly provides DC voltage for another part of the functional device of the meter; the second power supply of the power supply priority control circuit The switch controls the on-off of the second power supply and the meter functional device; and controls the on-off sequence of the second switch relative to the first switch through a voltage limiting device connected between the first switch and the second switch. 7. The power supply control method inside the electric meter according to claim 6, further comprising the step of cascading multiple power supply priority control circuits. 8. A power supply circuit inside an ammeter, characterized in that: it includes N-level power supply units cascaded with each other, each power supply unit includes a plurality of first power supplies, and the alternating current in the power supply is converted by its alternating step-down circuit The voltage part performs A/D conversion, and converts it into a first DC voltage through an electrically coupled DC/DC converter, which is used for a part of the ammeter function device to work; the first switch that controls the on-off of each first power supply and the ammeter function device ; a plurality of second power supplies, used to directly provide DC voltage for another part of the ammeter function device; a second switch for controlling the on-off of each second power supply and the ammeter function device; and connecting between the first switch and the second switch The voltage limiting device between them is used to control the corresponding on-off sequence of the second switch through the on-off of the first switch. 9. The power supply circuit inside the ammeter according to claim 8, characterized in that: the functional device of the ammeter includes a plurality of expandable external ports, and each expandable port is connected to a power supply unit, wherein each power supply unit is connected to The power supply sequence among previously cascaded power supply units is reduced step by step. 10. The power supply circuit inside the ammeter according to claim 9, characterized in that: the power supply circuit further comprises a hardware state machine connected to the plurality of expandable external ports, which is used to judge two The size of the logic level between the two power supply units to select different power supply units.