TWI567522B - Voltage converter circuit and voltage converter controller - Google Patents

Description

Voltage conversion circuit and voltage conversion controller

The invention relates to a voltage conversion circuit, in particular to a voltage conversion circuit which is coupled to a resistor of a photocoupler to achieve parameter setting, thereby reducing the required pins.

1 shows a schematic diagram of a voltage conversion circuit 10 of the prior art, which is a flyback control voltage conversion circuit including a corresponding voltage conversion controller 11 and a voltage conversion unit 12. Because in the voltage conversion unit 12, the primary side and the secondary side of the transformer are isolated from each other, in order to transmit the related information of the output voltage back to the voltage conversion controller 11 on the primary side of the transformer, optical coupling is used to couple the light. The light-emitting element 13a in the device transmits the output voltage-related information as an optical signal, and is received by the light-receiving element 13b in the optical coupler and input to the voltage conversion controller 11.

Since the voltage conversion controller 11 is usually an integrated circuit and the number of pins is limited, if the same pin can be used to achieve a plurality of different functions, more functions can be provided with a limited number of pins, or Reduce packaging costs.

The prior art related to the present case can be found in US 723313, US 2015/0023071, US 8704590, US 7764521.

In view of the above, the present invention provides a voltage conversion circuit and associated voltage conversion controller for using the same pin to achieve a variety of different functions with a limited number of pins.

In one aspect, the present invention provides a voltage conversion circuit comprising: a power stage circuit for converting an input voltage into an output voltage by switching one of the power switches; and an optical coupler for sensing The output voltage; a parameter setting component; and a voltage conversion controller for controlling the power switch, the voltage conversion controller comprising: a multi-function pin for externally connecting the parameter setting component and the optical coupler; a parameter sampling setting unit is configured to provide two different preset voltages to respectively sense two corresponding current values on the multi-function pin, the parameter sampling setting unit is configured according to the two preset voltages and the two corresponding current values The parameter value of the voltage conversion controller is set, wherein the two corresponding current values are related to the resistance value of the parameter setting component; or the parameter sampling setting unit provides two different preset currents to respectively sense the multifunctional connection The two corresponding voltage values on the foot, the parameter sampling setting unit sets the voltage conversion according to the two preset currents and the two corresponding voltage values The parameter value of the controller, wherein the two corresponding voltage values are related to the resistance value of the parameter setting component, whereby different parameter values of the component can be set by setting the parameter to set different parameter values.

In another aspect, the present invention provides a voltage conversion controller for controlling a voltage conversion circuit to convert an input voltage into an output voltage, and sensing the output voltage by an optical coupler. The conversion controller comprises: a multi-function pin externally connected with a parameter setting component and the optical coupler; and a parameter sampling setting unit for providing two different preset voltages for respectively sensing through the multi-function connection The two corresponding current values on the foot, the parameter sampling setting unit sets the parameter values of the voltage conversion controller according to the two preset voltages and the two corresponding current values, wherein the two corresponding current values are related to the parameter setting component a resistance value; or the parameter sampling setting unit provides two different preset currents to respectively sense two corresponding voltage values on the multi-function pin, and the parameter sampling setting unit is configured according to the two preset currents and the two corresponding voltage values And setting a parameter value of the voltage conversion controller, wherein the two corresponding voltage values are related to a resistance value of the parameter setting component, thereby The parameter setting elements of different resistance values, to set the parameter value differences.

In one preferred embodiment, the parameter setting component is a resistor.

In a preferred embodiment, the photocoupler includes a photosensitive element, and the parameter sampling setting unit provides the two preset voltages to respectively sense the two corresponding current values on the multi-function pin. The parameter setting component and the photosensitive component are coupled to one end of the parameter setting component, and the terminal is coupled to the multi-function pin.

In a preferred embodiment, the photocoupler includes a photosensitive element, and the parameter sampling setting unit provides the two preset currents to respectively sense the two corresponding voltage values on the multi-function pin, wherein The photosensitive element is coupled to the multi-function pin via the parameter setting component. In a preferred embodiment, the parameter sampling setting unit provides the two preset voltages to respectively sense the two corresponding current values on the multi-function pin, the parameter sampling setting unit includes: a voltage current a conversion circuit, the two preset voltages are converted into the two corresponding current values; a current voltage conversion circuit converts the two corresponding current values into corresponding two voltage sample values; and a difference calculation unit calculates the two voltage sample values The difference is to generate a parameter setting signal for setting the parameter value.

In one embodiment of the above embodiment, the difference calculation unit includes a sample holding unit and an addition and subtraction unit, and the sample holding unit captures one of the two voltage sample values, and the addition and subtraction unit is configured according to the sample and hold unit. And extracting the voltage sample value and another voltage sample value of the two voltage sample values to generate a difference between the two voltage sample values.

In one embodiment of the above embodiment, the difference calculation unit further includes a counter that counts the difference between the two voltage sample values to generate the parameter setting signal.

In a preferred embodiment, the parameter sampling setting unit provides the two preset currents to respectively sense the two corresponding voltage values on the multi-function pin, the parameter sampling setting unit includes: at least one current source The two preset currents are used to generate the two corresponding voltage values on the multi-function pin; and a difference calculation unit calculates a difference between the two corresponding voltage values to generate a parameter setting signal for Set the parameter value.

In one embodiment of the above embodiment, the difference calculation unit includes a sample holding unit and an addition and subtraction unit, and the sample holding unit captures one of the two corresponding voltage values, and the addition and subtraction unit is configured according to the sample holding unit. And extracting the corresponding voltage value and another corresponding voltage value of the two corresponding voltage values to generate a difference between the two voltage sample values.

In one of the above embodiments, the difference calculation unit further includes a counting unit that counts the difference between the two corresponding voltage values to generate the parameter setting signal.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

Referring to FIG. 2, a voltage conversion circuit 20 according to a first embodiment of the present invention is shown, which includes a parameter setting component R1, a voltage conversion controller 21, an optical coupler 22, and a power stage circuit 23. The parameter setting element R1 can be any element having a resistance value; in the embodiment, the parameter setting element R1 can be, for example but not limited to, a resistor. The voltage conversion controller is used to control the power switch M2 in the power stage circuit 23 to convert the input voltage Vin into an output voltage Vout. The photocoupler 22 includes a photosensitive element 221 and a light emitting element 222 for generating a feedback signal associated with the output voltage Vout. The operation mode of the voltage conversion controller 21 includes an initial mode for setting a parameter value of the voltage conversion controller 21 and a normal mode for controlling voltage conversion of the voltage conversion circuit 20. The voltage conversion controller 21 includes a multi-function pin COMP and a parameter sampling setting unit 211 (see FIGS. 3 and 5). The multi-function pin COMP is externally connected to the parameter setting element R1 and the photocoupler 22. In the embodiment of FIG. 2, the parameter setting component R1 and the photosensitive component 221 are coupled to one end of the parameter setting component R1, and the terminal is coupled to the multi-function pin COMP. In addition, the multi-function pin COMP can be coupled to a capacitor Ccomp to provide a function of filtering and filtering noise.

Referring to the embodiment of Fig. 2, please refer to Fig. 3. When the voltage conversion controller 21 is in the initial mode, the parameter sampling setting unit 211 provides two different preset voltages Vset1, Vset2 to the multi-function pin COMP, and respectively senses two corresponding current values I1 through the multi-function pin COMP. I2, the two corresponding current values I1, I2 correspond to the two preset voltages Vset1, Vset2 and are related to the resistance value of the parameter setting element R1, respectively. The parameter sampling setting unit 211 sets the parameter value of the voltage conversion controller according to the two preset voltages Vset1 and Vset2 and the two corresponding current values I1 and I2.

For example, in the embodiment, the parameter sampling setting unit 211 includes: a voltage current conversion circuit 2113, a current voltage conversion circuit 2111, and a difference calculation unit 2112. The voltage-current conversion circuit 2113 generates two corresponding current values I1 and I2 according to the two preset voltages Vset1 and Vset2, respectively, through the multi-function pin COMP. The current-voltage conversion circuit 2111 converts the two corresponding current values I1, I2 into voltage sample values. The difference calculating unit 2112 calculates a difference between the two voltage sampling values to generate a parameter setting signal for setting a parameter value of the voltage conversion controller.

In detail, for example, the voltage-current conversion circuit 2113 may include, for example but not limited to, the error amplifier EA1 and the transistor M3 shown in FIG. 3, and one input terminal of the error amplifier EA1 receives the preset voltage Vset1 or Vset2, and another The input end is coupled to the multi-function pin COMP; the output end of the error amplifier EA1 controls the transistor M3, and the lower end of the transistor M3 is also coupled to the multi-function pin COMP. When the circuit returns the balance, the voltages of the two input terminals of the error amplifier EA1 are equal (regardless of the component matching error), so the potential of the multi-function pin COMP is equal to the preset voltage Vset1 or Vset2. The preset voltage Vset1 or Vset2 will cause the multi-function pin COMP to flow out current, and the current will be shunted through the parameter setting component R1 and the photosensitive element 221, wherein when the preset voltage is Vset1, the current of the component R1 is set to Vset1 by the parameter. /R1, the current through the photosensitive element 221 is Id, and I1=(Vset1/R1)+Id; and, when the preset voltage is Vset2, the current through the parameter setting element R1 is Vset2/R1, passing through the photosensitive element 221 The current is Id and I2 = (Vset2/R1) + Id. Therefore, according to the difference between I1 and I2 and the difference between the preset voltages Vset1 and Vset2, the resistance value of the parameter setting component R1 (still expressed by R1) can be known: R1=(Vset2-Vset1)/(I2-I1) . That is to say, different parameter values of the component R1 can be set by setting parameters to set different parameter values.

It can be seen from the above calculation formula that since the preset voltages Vset1 and Vset2 are known, it is only necessary to obtain the difference between I1 and I2, and R1 can be known. However, since the preset voltages Vset1 and Vset2 are provided at different times, respectively, one must be stored to be subtracted from the other. When implemented as an analog circuit, for computational convenience, I1 and I2 can be converted to voltage first to facilitate sample storage. Therefore, in the present embodiment, the parameter sampling setting unit 211 includes a current voltage conversion circuit 2111 to convert the two corresponding current values I1, I2 into voltage sampling values. The current-voltage conversion circuit 2111 may include, for example but not limited to, a current mirror circuit for replicating I1 or I2, and a resistor Rg for converting I1 or I2 into a voltage sample value.

The difference calculating unit 2112 calculates a difference between the two voltage sampling values to generate a parameter setting signal for setting a parameter value of the voltage conversion controller. In this embodiment, the difference calculation unit 2112 includes a sample holding unit S/H and an addition and subtraction unit 21121. The sample and hold unit S/H extracts one of the two voltage samples and outputs a corresponding voltage Vc. 21121 is based on the corresponding voltage Vc and another voltage sample value of the two voltage samples to generate a difference between the two. In an embodiment, the output of the addition and subtraction unit 21121 can be used as an analog parameter setting signal. In another embodiment, the output of the addition and subtraction unit 21121 can be further counted via a counter count to generate a digital parameter setting signal.

The difference between the difference between the two preset voltages Vset1, Vset2 (Vset2-Vset1) divided by the two corresponding current values I1, I2 (I1-I2) is to subtract the current Id flowing through the photosensitive element 221, although at the initial In the mode, the circuit is just started, but it is not excluded that there may be a dark current on the photosensitive element 221, and this dark current may cause an error in calculating the resistance value of the parameter R1. However, when two preset voltages Vset1 and Vset2 are given, the influence of the current Id can be eliminated.

Referring to FIG. 4 and FIG. 5, in another embodiment, the photosensitive element 221 is coupled to the multi-function pin COMP via the parameter setting component R1 (ie, the parameter setting component R1 is coupled to the multi-function pin COMP and the photosensitive element 221). between). When the voltage conversion controller 21 is in the initial mode, the parameter sampling setting unit 211 provides two different preset currents Iset1 and Iset2, and flows out through the multi-function pin COMP to respectively sense two corresponding voltage values V1 on the multi-function pin COMP. V2 (refer to the voltage value VCOMP of the multi-function pin COMP, FIG. 5), the parameter sampling setting unit 211 sets the parameters of the voltage conversion controller 211 according to the two preset currents Iset1, Iset2 and the two corresponding voltage values V1, V2. value.

For example, in the embodiment of FIG. 5, the parameter sampling setting unit 211 includes: at least one current source (illustrated as two current sources, but can also be equivalently changed to a single variable current source) for providing the two Presetting currents Iset1, Iset2 to generate two corresponding voltage values V1, V2 on the multi-function pin COMP; and a difference calculating unit 2112 for calculating the difference between the two corresponding voltage values V1, V2 to generate a parameter Set the signal to set the parameter value of the voltage conversion controller. At least one current source provides two preset currents Iset1, Iset2, for example, two different currents can be provided by different variable current sources at different time points, or, as shown, by two current sources, according to The signals TA1, TA2 are controlled while providing two different currents at different times.

In detail, when the voltage conversion controller 21 is in the initial mode, at least one current source provides two preset currents Iset1 and Iset2, and flows out through the multi-function pin COMP to generate two corresponding voltage values V1 and V2 on the multi-function pin. . The two corresponding voltage values V1, V2 include the voltage across the parameter setting element R1 and the voltage across the photosensitive element 221. When the preset current is Iset1, the voltage across the parameter setting element R1 is equal to V1-(the voltage across the photosensitive element 221), that is, (Iset1*R1)=V1-(the voltage across the photosensitive element 221); When the preset current is Iset2, the voltage across the parameter setting element R1 is equal to V2-(the voltage across the photosensitive element 221), that is, (Iset2*R1) = V2- (the voltage across the photosensitive element 221). Therefore, according to the difference between V1 and V2 and the difference between the preset currents Iset1 and Iset2, the resistance value of the parameter setting component R1 (still expressed by R1) can be known: R1=(V2-V1)/(Iset2-Iset1) . In the above formula, the cross-pressure on the photosensitive member 221 is subtracted without affecting. That is to say, different parameter values of the component R1 can be set by setting parameters to set different parameter values.

The difference calculating unit 2112 calculates a difference between the two corresponding voltage values V1 and V2 to generate a parameter setting signal for setting a parameter value of the voltage conversion controller. In this embodiment, the difference calculation unit 2112 includes a sample holding unit S/H and an addition and subtraction unit 21121. The sample and hold unit S/H captures one of the two corresponding voltage values V1 and V2 and outputs a corresponding voltage Vc. The addition and subtraction unit 21121 generates another difference ΔV according to the corresponding voltage Vc and another voltage sample value of the corresponding voltage values V1, V2. In an embodiment, the output of the addition and subtraction unit 21121 can be used as an analog parameter setting signal. In another embodiment, the output of the addition and subtraction unit 21121 can be further counted via a counter count to generate a digital parameter setting signal.

According to the present invention, different parameter values of the component R1 can be set by setting parameters to set different parameter values for the voltage conversion controller 21, and it is not necessary to use an additional pin; in addition, although the multi-function pin COMP is also The photosensitive element 221 is coupled, but the current or voltage across the photosensitive element 221 does not affect the parameter setting.

The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. In the same spirit of the invention, various equivalent changes can be conceived by those skilled in the art. For example, the two current sources can be changed to a single variable current source capable of providing more than two currents; the current mirror circuit in the current-voltage conversion circuit can be changed to other forms of current mirror circuits; in the embodiment, the two circuits directly connected or Between components, other circuits or components that do not affect the main functions, such as switches, signal amplifying circuits, level shifting circuits, analog-to-digital conversion circuits, digital analog conversion circuits, temporary storage circuits, etc.; circuits implemented by analog circuits can be inserted. Can be changed to digital circuit to achieve; and so on. All such modifications may be made in accordance with the teachings of the present invention, and the scope of the present invention should be construed to cover the above and other equivalents.

10: voltage conversion circuit 11: voltage conversion controller 12: voltage conversion unit 20: voltage conversion circuit 21: voltage conversion controller 211: parameter sampling setting unit 2111: current voltage conversion circuit 2112: difference calculation unit 21121: addition and subtraction unit 2113: Voltage-current conversion circuit 22: Photocoupler 221: Photosensitive element 222: Light-emitting element 23: Power stage circuit Ccomp: Capacitor COMP: Multi-function pin Count: Counter EA1: Error amplifier GATE, CS: Pins I1, I2: Corresponding current value Id: current Iset1, Iset2: preset current M1, M2: power switch M3: transistor R1: parameter setting component Rg: resistance S/H: sample and hold unit TA1, TA2: control signal V1, V2: corresponding voltage Value ΔV: difference Vc: corresponding voltage Vcomp: voltage value Vin: input voltage Vout: output voltage Vset1, Vset2: preset voltage

[Fig. 1] shows a schematic diagram of a voltage conversion circuit of the prior art; [2-3] shows a schematic diagram of a voltage conversion circuit and a voltage conversion controller according to an embodiment of the present invention; [Fig. 4-5] shows the present invention A schematic diagram of a voltage conversion circuit and a voltage conversion controller of another embodiment.

21: voltage conversion controller 211: parameter sampling setting unit 2111: current voltage conversion circuit 2112: difference calculation unit 21121: addition and subtraction unit 2113: voltage current conversion circuit 221: (optical coupler) photosensitive element Ccomp: capacitance COMP: Multi-function pin Count: Counter EA1: Error amplifier I1, I2: Corresponding current value Id: Current M3: Transistor Rg: Resistor R1: Parameter setting element S/H: Sample holding unit Vc: Corresponding voltage Vset1, Vset2: Preset Voltage

Claims (17)

A voltage conversion circuit comprising: a power stage circuit for converting an input voltage into an output voltage by switching one of the power switches; an optocoupler for sensing the output voltage; a parameter setting component; And a voltage conversion controller for controlling the power switch, the voltage conversion controller comprising: a multi-function pin externally connected to the parameter setting component and the optical coupler; and a parameter sampling setting unit for providing The two preset voltages respectively sense two corresponding current values on the multi-function pin, and the parameter sampling setting unit sets the voltage conversion controller according to the two preset voltages and the two corresponding current values. a parameter value, wherein the two corresponding current values are related to a resistance value of the parameter setting component; or the parameter sampling setting unit provides two different preset currents to respectively sense two corresponding voltage values on the multi-function pin, The parameter sampling setting unit sets the parameter values of the voltage conversion controller according to the two preset currents and the two corresponding voltage values, wherein the two corresponding Pressure value related to the parameter setting of the resistance value of the element, whereby, the parameter can be set by the setting elements of different resistance values, to set the parameter value differences. The voltage conversion circuit of claim 1, wherein the parameter setting component is a resistor. The voltage conversion circuit of claim 1, wherein the optical coupler comprises a photosensitive element, and the parameter sampling setting unit provides the two preset voltages to respectively sense the through the multi-function pin Two corresponding current values, wherein the parameter setting component and the photosensitive element are coupled to one end of the parameter setting component, and the terminal is coupled to the multi-function pin. The voltage conversion circuit of claim 1, wherein the photocoupler comprises a photosensitive element, and the parameter sampling setting unit provides the two preset currents to respectively sense the two on the multi-function pin Corresponding to the voltage value, wherein the photosensitive element is coupled to the multi-function pin via the parameter setting component. The voltage conversion circuit of claim 1, wherein the parameter sampling setting unit provides the two preset voltages to respectively sense the two corresponding current values on the multi-function pin, the parameter sampling setting unit The method comprises: a voltage-current conversion circuit, converting the two preset voltages into the two corresponding current values; a current-voltage conversion circuit, converting the two corresponding current values into corresponding two-voltage sampling values; and a difference calculation unit, calculating The difference between the two voltage samples is used to generate a parameter setting signal for setting the parameter value. The voltage conversion circuit of claim 5, wherein the difference calculation unit comprises a sample holding unit and an addition and subtraction unit, wherein the sample holding unit captures one of the two voltage sample values, the addition and subtraction unit is The voltage sample value captured by the sample and hold unit and another voltage sample value of the two voltage sample values produce a difference between the two voltage sample values. The voltage conversion circuit of claim 6, wherein the difference calculation unit further comprises a counter, and the difference between the two voltage samples is counted to generate the parameter setting signal. The voltage conversion circuit of claim 1, wherein the parameter sampling setting unit provides the two preset currents to respectively sense the two corresponding voltage values on the multi-function pin, the parameter sampling setting unit includes : At least one current source for providing the two preset currents to generate the two corresponding voltage values on the multi-function pin; and a difference calculation unit for calculating a difference between the two corresponding voltage values to generate a parameter setting Signal to set the value of this parameter. The voltage conversion circuit of claim 8, wherein the difference calculation unit comprises a sample holding unit and an addition and subtraction unit, wherein the sample holding unit captures one of the two corresponding voltage values, and the addition and subtraction unit is The corresponding voltage value captured by the sample and hold unit and another corresponding voltage value of the two corresponding voltage values generate a difference between the two voltage sample values. The voltage conversion circuit of claim 9, wherein the difference calculation unit further comprises a counter that counts the difference between the two corresponding voltage values to generate the parameter setting signal. A voltage conversion controller for controlling a voltage conversion circuit to convert an input voltage into an output voltage, and sensing the output voltage by an optical coupler comprising: a multi-function pin Using a parameter setting component and the optical coupler; and a parameter sampling setting unit for providing two different preset voltages to respectively sense two corresponding current values on the multi-function pin, the parameter The sampling setting unit sets the parameter value of the voltage conversion controller according to the two preset voltages and the two corresponding current values, wherein the two corresponding current values are related to the resistance value of the parameter setting component; or the parameter sampling setting unit provides The two preset currents respectively sense two corresponding voltage values on the multi-function pin, and the parameter sampling setting unit sets the parameters of the voltage conversion controller according to the two preset currents and the two corresponding voltage values. a value, wherein the two corresponding voltage values are related to a resistance value of the parameter setting component, thereby setting different resistance values of the component by setting the parameter To set the parameter value differences. The voltage conversion controller of claim 11, wherein the parameter sampling setting unit provides the two preset voltages to respectively sense the two corresponding current values on the multi-function pin, and the parameter sampling setting The unit comprises: a voltage-current conversion circuit, converting the two preset voltages into the two corresponding current values; a current-voltage conversion circuit, converting the two corresponding current values into corresponding two-voltage sampling values; and a difference calculation unit, Calculating the difference between the two voltage samples to generate a parameter setting signal for setting the parameter value. The voltage conversion controller according to claim 12, wherein the difference calculation unit comprises a sample holding unit and an addition and subtraction unit, and the sample holding unit captures one of the two voltage sample values, the addition and subtraction unit The difference between the two voltage samples is generated based on the voltage sample value captured by the sample and hold unit and another voltage sample value of the two voltage sample values. The voltage conversion controller of claim 13, wherein the difference calculation unit further comprises a counting unit that counts the difference between the two voltage sampling values to generate the parameter setting signal. The voltage conversion controller of claim 11, wherein the parameter sampling setting unit provides the two preset currents to respectively sense the two corresponding voltage values on the multi-function pin, the parameter sampling setting unit The method includes: two current sources for respectively providing the two preset currents to generate the two corresponding voltage values on the multi-function pin; and a difference calculation unit, calculating a difference between the two corresponding voltage values to generate a Parameter setting signal to set the parameter value. The voltage conversion controller of claim 15, wherein the difference calculation unit comprises a sample holding unit and an addition and subtraction unit, wherein the sample holding unit captures one of the two corresponding voltage values, the addition and subtraction unit And generating a difference between the two voltage sample values according to the corresponding voltage value captured by the sample and hold unit and another corresponding voltage value of the two corresponding voltage values. The voltage conversion controller of claim 16, wherein the difference calculation unit further comprises a counting unit that counts the difference between the two corresponding voltage values to generate the parameter setting signal.