WO2013026344A1

WO2013026344A1 - Automatic voltage switch and implementation method thereof

Info

Publication number: WO2013026344A1
Application number: PCT/CN2012/079242
Authority: WO
Inventors: 杨义根
Original assignee: Yang Yigen
Priority date: 2011-08-23
Filing date: 2012-07-27
Publication date: 2013-02-28
Also published as: CN102299617A; CN102299617B

Abstract

An automatic voltage switch and an implementation method thereof. The automatic voltage switch comprises: a voltage amplitude sampling circuit used for sampling an alternating current voltage amplitude and outputting a sampled voltage value; a voltage state sampling circuit used for sampling a alternating current voltage waveform and outputting a sampled waveform signal; a microprocessor (U1) used for determining whether an alternating current voltage at an alternating current input end is a first voltage or a second voltage according to the sampled voltage value, determining whether the voltage is in a stable state according to the sampled waveform signal, and sending a voltage-doubling rectification instruction when the alternating voltage is a first voltage and is in a stable state. The automatic voltage switch automatically determines whether a currently input alternating current voltage is a first voltage or a second voltage, and when it is detected that the input alternating current voltage is in a stable state, sends a voltage-doubling rectification instruction to control the direct current voltage. The automatic voltage switch has a simple circuit structure, low cost and low power consumption, and is safe and reliable.

Description

Automatic voltage switch and its implementation method

The present invention relates to a switching circuit in the field of electronic technology, and more particularly to an automatic voltage switch for automatically determining whether to perform voltage doubler rectification by an alternating current power supply line voltage and an implementation method thereof. Background technique

The AVS08 product from STMicroelectronics is a 110V / 220V AC power line voltage auto selector kit for switching power supplies up to 200W. This kit is also known as an automatic voltage switch, abbreviated as AVS in English.

As shown in Figure 1, it is a typical application circuit diagram of AVS08. The AVS08 is mainly composed of a controller IC1 of the AVSIBCP08 and a two-way thyristor VS1 of the AVS08CB or AVS08CB1.

A series circuit consisting of resistor R4, resistor R5, resistor D5 and capacitor C4 provides the supply voltage to controller IC1. The first pin Vss of controller IC1 is a shunt regulator, which provides -9V output (maximum current Iss is 25mA). A resistor divider consisting of resistor R1 and resistor R2 is used as the AC line voltage for measuring input. , so that the voltage on the 8th pin of the controller IC1 changes with the AC input voltage. The control function of the AVS08 is done by comparing the AC line voltage to the threshold voltage. The peak voltage detection high threshold Vth = 4.25V on the comparator with a hysteresis voltage VH (typically 0.4v).

The AVS08 is compatible with 50Hz or 60Hz AC line frequencies and operates over two AC line voltage ranges. The first voltage varies from 88V to 132V (AC line rated voltage is 110V, 60Hz); the second voltage varies from 176 to 276V (AC supply line rated voltage is 220V, 50Hz). When the input voltage is in the first voltage range, the controller IC1 drives the triac VS1 to be turned on, the bridge operates in the double voltage mode; when the input voltage is in the second voltage range, the triac VS1 blocks, the input circuit Works in full bridge rectification mode. Whether the input is the first voltage or the second voltage, lose The DC voltage values are the same.

Existing circuits have the following technical defects:

1. Controller IC1 is a special chip with high price, which leads to high cost of automatic voltage switch.

2. The controller IC1 does not have a standby port and a power-on detection port, and there is no standby control circuit. The entire automatic voltage switch has a large power consumption. Summary of the invention

In order to overcome the problems of the prior art, the present invention provides an automatic voltage switch and an implementation method thereof, which automatically determine whether the current AC input voltage is the first voltage or the second voltage, and when detecting that the AC input voltage is already in a stable state, The voltage doubler rectification command controls the output DC voltage, which is safe and reliable and has a low implementation cost.

The invention is implemented by the following technical solution: an automatic voltage switch, comprising: an AC input terminal for inputting an AC voltage, the AC voltage is a first voltage or a second voltage; and a DC output terminal for outputting a DC voltage; a rectifier bridge and a triac connected in sequence between the AC input terminal and the DC output terminal; a voltage amplitude sample circuit for sampling the AC voltage amplitude and outputting the sample voltage value; for sampling the AC voltage waveform And outputting a voltage state sample circuit of the sample waveform signal; determining whether the AC voltage of the AC input terminal is the first voltage or the second voltage according to the sample voltage value, determining whether the AC voltage is in a stable state according to the sample waveform signal, and a microprocessor that issues a voltage doubler rectification command when the AC voltage is the first voltage and is in a steady state; wherein, the voltage amplitude sampling circuit is connected to the voltage determination port of the microprocessor, and the voltage state sampling circuit is connected to the stability of the microprocessor. The state determination port, the control output port of the microprocessor is coupled to the control end of the triac.

In a preferred embodiment, the microprocessor reaches a predetermined amplitude by detecting a second period of time during which the sample waveform signal reaches the predetermined amplitude during the rising/falling phase of the current cycle, and during the rising/falling phase of the previous cycle. The first time, it is judged whether the difference between the second time and the first time is A fixed value, if yes, a voltage doubler rectification command is issued when the AC voltage is the first voltage.

In a preferred embodiment, the voltage amplitude sampling circuit comprises: a first diode connected to the AC input terminal of the anode, a cathode connected in series with a fifth resistor connected to the voltage determination port of the microprocessor, and a voltage determination port of the microprocessor Connect the seventh resistor between the ground.

In a preferred embodiment, the voltage state sampling circuit includes: a first diode connected to the AC input terminal of the anode, a cathode connected to the steady state determination port of the microprocessor through the fourth resistor, and a steady state determination port between the ground and the ground Connected to the tenth resistor.

In a preferred embodiment, the automatic voltage switch further includes: a power supply that outputs a continuous pulse signal in an operating state and outputs a discontinuous pulse signal in a standby state; and the power supply is connected to the power supply of the microprocessor through the power supply circuit. Port, the microprocessor determines whether the power supply is a continuous pulse signal to determine whether it is in the working state.

In a preferred embodiment, the automatic voltage switch further includes: a standby sampling circuit connected between the power supply and the standby detection port of the microprocessor, and the standby sampling circuit includes a transformer connected to the power supply at the primary side, and the transformer The secondary side is connected to the anode of the second diode, and a high frequency filter is connected between the cathode of the second diode and the standby detection port of the microprocessor.

In a preferred embodiment, the triac is triggered by a pulse or DC signal.

In addition, the present invention also provides an implementation method of an automatic voltage switch, which comprises the steps of: outputting a sample voltage value from a voltage amplitude sample circuit, and outputting a sample voltage value, and the microprocessor determines the exchange according to the sample voltage value. Whether the AC voltage at the input terminal is the first voltage or the second voltage;

The voltage state signal is used to sample the AC voltage waveform, and the sample waveform signal is output. The microprocessor determines whether the AC voltage is in a stable state according to the sample waveform signal, and sends out when the AC voltage is the first voltage and is in a steady state. Double voltage rectification instruction;

The bidirectional thyristor is turned on/off according to the voltage doubler rectification command, and the rectification bridge connected to the AC input terminal is controlled to select different working modes to control the DC output voltage of the DC output terminal.

In a preferred embodiment, the step of determining whether the AC voltage is already in a steady state comprises: Detecting a second time when the sample waveform signal reaches a predetermined amplitude in a rising phase/down phase of the current cycle, and a first time reaching a predetermined amplitude in a rising phase/down phase of the previous cycle; determining the second time and the first time Whether the difference in time is a fixed value, and if so, the microprocessor issues a voltage doubler rectification command when the AC voltage is the first voltage.

In a preferred embodiment, the method for implementing the automatic voltage switch further includes the steps of: detecting whether the power supply is a continuous pulse signal, and controlling the microprocessor to enter a standby state when detecting that the power supply is a discontinuous pulse signal, When it is detected that the power supply is a continuous pulse signal, the control microprocessor maintains the working state or enters the working state from the standby state;

Wherein, the power supply source outputs a continuous pulse signal in an operating state, and outputs a discontinuous ripple signal in a standby state.

Compared with the prior art, the present invention has the following beneficial effects:

1. The microprocessor of the present invention automatically recognizes that the AC voltage Uin is 110V/220V through the voltage amplitude sampling circuit, and the microprocessor detects whether the AC voltage Uin is stable through the voltage state sampling circuit, only when the input AC voltage Uin is at In the steady state, the microprocessor sends a voltage doubler rectification command to control the output DC voltage. Therefore, it is possible to effectively detect the contact failure of the AC input terminal and avoid misjudging the AC voltage Uin, which has high operational reliability.

2. The invention utilizes the waveform characteristic of the power supply Ucc to control the automatic voltage switch to switch between the working state and the standby state, without adding an additional standby circuit, the microprocessor performs standby (standby state) and power-on detection (working state), only When it is in working state, the microprocessor will issue a voltage doubler rectification command. Therefore, the circuit structure for implementing the standby function is simple and the implementation cost is low.

3. The microprocessor of the invention is realized by a single chip microcomputer, and has the advantages of simple implementation and low power consumption. DRAWINGS

1 is a circuit diagram of a conventional automatic voltage switch;

Figure 2 is a circuit diagram showing the first embodiment of the automatic voltage switch of the present invention; 3 is a waveform diagram of a sample waveform signal;

Figure 4 is a waveform diagram of the power supply Ucc;

Fig. 5 is a circuit diagram showing a second embodiment of the automatic voltage switch of the present invention. detailed description

As shown in FIG. 2, in the first embodiment of the present invention, the automatic voltage switch includes: an AC input terminal for inputting an AC voltage Uin, and the AC voltage Uin is a first voltage or a second voltage; The DC output terminal of the DC voltage Uout; the rectifier bridge DB1 and the triac VS1 connected in sequence between the AC input terminal and the DC output terminal; the microprocessor U1 implemented by the single chip microcomputer, and the voltage determination port thereof (third reference) The foot is connected to the AC input terminal through the voltage amplitude sampling circuit, and the steady state determination port (the second pin) of the microprocessor U1 is connected to the AC input terminal through the voltage state sampling circuit, and the power port of the microprocessor U1 (4th) The pin is connected to the power supply Ucc through the power supply circuit, and the standby detection port (the first pin) of the microprocessor U1 is connected to the power supply Ucc through the standby sampling circuit, and the control output port (the fifth pin) of the microprocessor U1 is passed. The control command output circuit is connected to the control terminal of the triac VS1.

When the AC voltage Uin is the first voltage, the microprocessor U1 issues a voltage doubler rectification command to drive the triac VS1 to be turned on, the rectifier bridge DB1 operates in the double voltage mode; when the alternating voltage Uin is the second voltage, the two-way controllable Silicon VS1 is blocked, and rectifier bridge DB1 operates in full-bridge rectification mode.

The first voltage varies from 88V to 132V; the second voltage varies from 176 to 276V. The following is an example in which the first voltage is AC 110V and the second voltage is AC 220V.

The voltage amplitude sampling circuit comprises: a first diode D1 connected to the AC input end of the anode, a cathode connected to the fifth resistor R5 connected to the voltage determination port of the microprocessor U1, and a voltage determination port of the microprocessor U1 and the ground The seventh resistor R7 is connected in parallel.

After the AC voltage Uin is rectified by the first diode D1, the voltage is divided by the fifth resistor R5 and the seventh resistor R7, and the voltage division on the seventh resistor R7 is the voltage value of the sample, and the voltage value is Send in The voltage determination port of the microprocessor U1 determines whether the current AC voltage Uin is AC 220V or AC 110V according to the sample voltage value; when the AC voltage Uin is AC 110V, the control output port of the microprocessor U1 The voltage doubler rectification command is issued to control the two-way thyristor VS1 to be turned on.

For example, when the AC voltage Uin is AC 220V, the voltage division on the seventh resistor R7 is 15 V; under the same condition, when the AC voltage Uin is AC 110V, the voltage division on the seventh resistor R7 is 7.5. V. Therefore, a threshold value is set in the microprocessor U1. When the input sample voltage value is greater than the threshold value, the microprocessor U1 determines that the current AC voltage Uin is AC 220V. Otherwise, the microprocessor U1 determines the current AC voltage. Uin is AC 110V.

The voltage state sampling circuit includes: a tenth resistor R10 divided by the fourth resistor R4, the fourth resistor R4 is connected in series with the tenth resistor R10, and the fourth resistor R4 is connected to the common end of the tenth resistor R10. The steady state determination port of U1. The voltage division signal on the tenth resistor R10 is a sample waveform signal, and the microprocessor U1 detects whether the voltage division signal on the tenth resistor R10 is in a stable state.

As shown in Fig. 3, the abscissa t represents time, and the ordinate U represents the amplitude of the sample waveform signal, that is, the voltage division signal on the tenth resistor R10. The AC voltage Uin is a sine wave; after the first diode D1 is rectified, the fourth resistor R4 is connected in series with the tenth resistor R10 to divide the rectified AC voltage Uin, and the voltage division signal on the tenth resistor R10 is 釆Sample waveform signal. Therefore, the stable state determination port of the microprocessor U1 determines whether the waveform of the sample waveform signal is stable in each successive period by detecting the sample waveform signal, that is, whether the AC voltage Uin is stable or not. Only when it is judged that the AC voltage Uin is already in a stable state, the control output port of the microprocessor U1 issues a voltage doubler rectification command to control the triac VS1, and the DC output terminal outputs a DC voltage.

Specifically, for the waveform data of the sample waveform signal, the microprocessor U1 reads the time during which the waveform reaches a certain amplitude in the rising phase (or the falling phase) in each cycle, and uses two adjacent ones. The time difference between the cycles reaches the same amplitude, and it is judged whether the time difference is a fixed value. If yes, it indicates that the AC voltage Uin is already in a stable state. For example, in the current cycle, the waveform reaches a certain amplitude time t1 in the rising phase, and the waveform is in the rising phase in the adjacent previous cycle. The segment reaches a time t2 at which the amplitude is determined, then the time difference T = t1 - t2. It is judged by the microprocessor U1 whether or not the time difference T is equal to a fixed value. The microprocessor U1 detects that the time difference T is equal to a fixed value, indicating that the current input AC voltage Uin is already in a steady state, and a voltage doubler rectification command is issued.

In a preferred embodiment, the time difference is calculated by detecting the time during which the waveform waveform signal reaches zero in the falling phase during each period.

Among them, the two-way thyristor VS1 sample pulse trigger mode or DC trigger mode.

In a preferred embodiment, the control command output circuit comprises: a control output port of the microprocessor U1 connected in series to the current limiting eighth resistor R8 is connected to the base of the second transistor T2, and the emitter of the second transistor T2 is grounded. The collector is connected in series to the current limiting ninth resistor R9 to connect the control terminal of the triac VS1.

In another preferred embodiment, the control output port of the microprocessor U1 is directly connected or serially connected to a control circuit of the triac VS1.

As shown in Fig. 4, the power supply Ucc outputs a continuous pulse signal in the operating state and a discontinuous pulse signal in the standby state.

The power supply circuit includes: a transformer TR1 connected to the power supply Ucc; an anode connected to the third diode D3 of the secondary side of the transformer TR1; connected in series with the cathode of the third diode D3 and the standby detection port of the microprocessor U1 A third resistor R3 for current limiting. In the working state, the power supply Ucc for the high-frequency continuous square wave signal is rectified by the third diode D3, and after being limited by the third resistor R3, the power supply of the microprocessor U1 is output to the power of the microprocessor U1. port.

The standby sampling circuit includes: a transformer TR1 whose primary side is connected to the power supply Ucc, and a secondary side of the transformer TR1 connected to the anode of the second diode D2; at the cathode of the second diode D2 and the standby detection port of the microprocessor U1 Connect the high frequency filter. Specifically, the high frequency filter includes: a first resistor R1 connected in series between the cathode of the second diode D2 and the power port of the microprocessor U1; respectively connected to the power port of the microprocessor U1 and the ground A first capacitor C1 and a second resistor R2 are in between. The high frequency pulse signal in the power supply Ucc is filtered by the high frequency filter. When in the working state, the high-frequency pulse signal of the power supply Ucc is completely filtered by the high-frequency filter, and the standby detection port of the microprocessor U1 cannot detect the low-frequency pulse signal, so the microprocessor U1 remains in the working state; When Ucc outputs a discontinuous high-frequency pulse signal, the high-frequency pulse signal of the power supply Ucc is completely filtered by the high-frequency filter, and the low-frequency pulse signal is output to the standby detection port of the microprocessor U1, and the microprocessor U1 enters the standby state.

Therefore, it is judged by the microprocessor U1 whether the power supply voltage Ucc is a continuous pulse signal, and if so, it indicates that the current state is the operating state, otherwise it indicates that the current state is the standby state. Only when the microprocessor U1 judges that the current working state is based on whether the current AC voltage Uin is AC 220V or AC 110V, and the AC voltage Uin is in a steady state, the voltage doubler rectification command is issued to the two-way controllable. Silicon VS1.

As shown in FIG. 5, in the second embodiment of the present invention, the voltage amplitude sampling circuit includes: a first diode D1 having an anode connected to the AC input terminal, and a cathode connected in series with a fifth resistor R5 and a cathode of the step-down tube DW1. The anode of the step-down tube DW1 is connected to the voltage determination port of the microprocessor U1, and the sixth resistor R6 and the seventh resistor are connected in series between the cathode of the step-down tube DW1 and the anode and the anode of the step-down tube DW1, respectively. R7. The anode output voltage of the step-down tube DW1 is used to determine the voltage to the voltage of the microprocessor U1.

For example, when the AC voltage Uin is AC 220V, the voltage divider resistor R6 is divided into 15V, and the step-down tube DW1 is stepped down to 5V. The output voltage of the step-down tube DW1 is: 15-5=10V. . Under the same conditions, when the AC voltage Uin is AC 110V, the voltage divider resistor R6 is divided into 7.5V. Then, the voltage value of the output of the step-down tube DW1 is 7.5-5=2.5V. Therefore, according to the specific parameters of the fifth resistor R5, the sixth resistor R6 and the step-down tube DW1 in the voltage amplitude sampling circuit, a threshold value is set in the microprocessor U1, when the input sample voltage value is greater than the width When the value is, the microprocessor U1 determines that the current AC voltage Uin is AC 220V. Otherwise, the microprocessor U1 determines that the current AC voltage Uin is AC llOVo. The voltage state sampling circuit comprises: a first diode D1 connected to the AC input end of the anode, the cathode of which is connected to the base of the first transistor T1 through a fourth resistor R4 for current limiting, the emitter of the first transistor T1 is grounded, The collector is connected to the steady state determination port of the microprocessor U1. Therefore, the voltage state sampling circuit samples the AC voltage Uin, and obtains a sample waveform signal at the collector of the first transistor T1.

The microprocessor U1 detects whether the sample waveform signal on the emitter of the first transistor T1 is in a stable state, and can determine whether the AC voltage Uin is in a stable state. The specific judgment basis and principle are the same as in the first embodiment, Repeat the description.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

Rights request

1. An automatic voltage switch, comprising: an AC input terminal for inputting an AC voltage, the AC voltage is a first voltage or a second voltage; a DC output terminal for outputting a DC voltage; and sequentially connected to the AC input terminal and the DC a rectifier bridge and a triac between the output terminals; wherein the automatic voltage switch further comprises:

A voltage amplitude sample circuit for sampling the amplitude of the AC voltage and outputting the sample voltage value; a voltage state sample circuit for outputting the sampled AC voltage waveform, outputting the sample waveform signal; for determining the voltage value according to the sample voltage Whether the AC voltage at the AC input terminal is the first voltage or the second voltage, and the microprocessor that determines whether the AC voltage is already in a stable state according to the sample waveform signal and issues a voltage doubler rectification command when the AC voltage is the first voltage and is in a steady state ;

Wherein, the voltage amplitude sampling circuit is connected to the voltage determining port of the microprocessor, the voltage state sampling circuit is connected to the stable state determining port of the microprocessor, and the control output port of the microprocessor is coupled to the control end of the triac.

2. The automatic voltage switch according to claim 1, wherein the microprocessor detects the second time of the predetermined amplitude in the rising/falling phase of the current cycle by detecting the waveform signal, and the rise in the previous cycle. The first time when the phase/down phase reaches the predetermined amplitude determines whether the difference between the second time and the first time is a fixed value, and if so, the voltage doubler rectification command is issued when the alternating voltage is the first voltage.

3. The automatic voltage switch according to claim 1, wherein the voltage amplitude sampling circuit comprises: a first diode connected to the alternating current input terminal, and a cathode connected in series with a fifth resistor connected to the voltage determining port of the microprocessor. And the voltage determination port of the microprocessor and the ground are connected to the seventh resistor.

4. The automatic voltage switch according to claim 1, wherein the voltage state sampling circuit The method includes: a first diode connected to the AC input end of the anode, a cathode connected to the steady state determination port of the microprocessor through the fourth resistor, and a steady state determination port and the ground connected to the tenth resistor.

The automatic voltage switch according to claim 1, wherein the automatic voltage switch further comprises: a power supply that outputs a continuous pulse signal in an operating state and outputs a discontinuous pulse signal in a standby state; The power supply circuit is connected to the power port of the microprocessor, and the microprocessor determines whether the power supply is a continuous pulse signal to determine whether it is in a working state.

The automatic voltage switch according to claim 4, wherein the automatic voltage switch further comprises: a standby sampling circuit connected between the power supply and the standby detection port of the microprocessor; wherein, the standby sampling circuit The utility model comprises: a transformer connected to the power supply on the primary side, a secondary side of the transformer connected to the anode of the second diode, and a high frequency filter connected between the cathode of the second diode and the standby detection port of the microprocessor.

7. An automatic voltage switch according to any of claims 1-6, characterized in that the triac is triggered by a pulse signal or a direct current signal.

8. A method for realizing an automatic voltage switch, the method comprising the steps of: sampling a voltage amplitude from a voltage amplitude sample circuit, outputting a sample voltage value, and determining, by the microprocessor, a voltage value according to the sample Determining whether the AC voltage at the AC input is the first voltage or the second voltage;

The bidirectional thyristor is turned on/off according to the voltage doubler rectification command, and the rectifier bridge connected to the AC input terminal is controlled to select different working modes, and the DC output terminal is controlled to output a DC voltage.

9. The method of realizing an automatic voltage switch according to claim 8, wherein the step of determining whether the AC voltage is already in a stable state comprises:

Detecting a second time when the sample waveform signal reaches a predetermined amplitude in a rising phase/down phase of the current cycle, and a first time reaching a predetermined amplitude in a rising phase/down phase of the previous cycle; determining the second time and the first time Whether the difference in time is a fixed value, and if so, the microprocessor issues a voltage doubler rectification command when the AC voltage is the first voltage.

The method for realizing the automatic voltage switch according to claim 8 or 9, wherein the method further comprises the steps of:

Detect whether the power supply is a continuous pulse signal, and when the power supply is detected as a discontinuous pulse signal, the microprocessor is controlled to enter a standby state, and when the power supply is detected as a continuous pulse signal, the microprocessor is kept in a working state. Or enter the working state from the standby state;