TWI437405B - Adaptive two-stage voltage regulator and method for controlling same - Google Patents

Description

Adaptive two-stage voltage regulator circuit and control method thereof

The invention relates to an adaptive two-stage voltage regulator circuit (Voltage Regulator) and a control method thereof, in particular to an adaptive adjustment of an intermediate voltage according to a relationship between an input voltage and an output voltage, so as to save energy and adaptability. Two-stage voltage regulator circuit and control method.

Referring to Figure 1, in order to meet the needs of some applications, a two-stage voltage regulation is required in the power supply device, and the input voltage Vin is first converted into an intermediate voltage Vm and then converted into an output voltage Vout. The purpose is to pass the first-stage voltage regulating circuit 10 to efficiently convert the voltage and then pass through the second-stage linear regulator circuit 20 to filter the chopping noise in the intermediate voltage Vm. For example, when the load circuit is an active matrix organic light emitting diode (AMOLED), it may be necessary to use such a two-stage voltage stabilizing circuit.

Taking the load circuit as an AMOLED as an example, in one application, the required output voltage Vout is 4.6V, the input voltage Vin is the battery voltage, and may vary between 2.5 and 4.8V, and the voltage regulating circuit 10 is boost converter. Circuit. Referring to FIG. 2, since the input voltage Vin may be 4.8V, in order to ensure that the boost converter circuit can work normally, the output voltage Vm of the voltage regulating circuit 10 is set to 4.9V (the output voltage of the boost converter circuit must be greater than Input voltage; if the voltage Vm is set to 4.8V or less, the boost converter circuit cannot operate when the input voltage Vin is 4.8V, and the intermediate voltage Vm of 4.9V is converted to 4.6V by the linear regulator circuit 20. The output voltage Vout.

In the above arrangement, it can be seen from the figure that when the voltage value of the input voltage Vin is 2.5~4.6V, the voltage difference ΔV of 4.9V-4.6V=0.3V will be caused, which increases the energy consumption of the circuit.

In view of this, the present invention is directed to the above-mentioned deficiencies of the prior art, and proposes an adaptive two-stage voltage regulator circuit and control method to save energy.

One of the objects of the present invention is to provide an adaptive two-stage voltage regulator circuit.

Another object of the present invention is to provide a method of controlling a two-stage voltage regulator circuit.

In order to achieve the above object, in one aspect, the present invention provides an adaptive two-stage voltage regulator circuit comprising: a voltage regulating circuit for generating an intermediate voltage (Vm) according to an input voltage (Vin), wherein The input voltage is less than or equal to a maximum value (Vin_max); a linear regulator circuit generates an output voltage (Vout) according to the intermediate voltage; and an intermediate voltage control circuit that receives (1) an indicator signal related to the input voltage, And one of the following: (2a) the indicator signal of the output voltage, or (2b) the preset reference signal, and adjust the intermediate voltage according to the received signal, so that when the input voltage is less than or equal to the output voltage: Vm =Vout+ΔV, and (Vout+ΔV)<Vin_max.

In another aspect, the present invention provides a method for controlling a two-stage voltage stabilization circuit, comprising: generating an intermediate voltage (Vm) according to an input voltage (Vin), wherein the input voltage is less than or equal to a maximum value (Vin_max) An output voltage (Vout) is generated according to the intermediate voltage; (1) an indicator signal related to the input voltage, and one of: (2a) an indicator signal related to the output voltage, or (2b) a preset The reference signal; and adjusting the intermediate voltage according to the received signal such that when the input voltage is less than or equal to the output voltage: Vm=Vout+ΔV, and (Vout+ΔV)<Vin_max.

In the above adaptive two-stage voltage regulator circuit or the control method thereof, when the input voltage is greater than the output voltage, the intermediate voltage may be a single-order or multi-step step shape, or an irregular shape, or Vm=Vin+ΔV .

When the intermediate voltage is a single-order or multi-step step shape, the index signal (1) related to the input voltage can be compared with the indicator signal (2a) or the preset reference signal (2b) regarding the output voltage, and compared according to As a result, a reference voltage is selected and supplied to the voltage regulating circuit.

When Vm=Vin+ΔV, in one embodiment, the Vin index and the Vout index can be converted into a current signal, and the Vout index is subtracted from the Vin index. After the obtained positive difference value is converted into a voltage signal, it is superimposed on a reference voltage and supplied to the voltage regulating circuit.

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 the first embodiment of FIG. 3, in order to facilitate comparison with FIG. 2, it is assumed here that the input voltage Vin varies between 2.5 and 4.8 V, and the required output voltage Vout is 4.6 V. In fact, the same concept is applicable. The output voltage Vout does not have to be 4.6V in all voltage ranges, and the maximum value Vin_max of the input voltage does not have to be 4.8V.

As shown in FIG. 3, the focus of this embodiment is that the intermediate voltage Vm is adaptively changed according to the input voltage Vin and the output voltage Vout. When the input voltage Vin is less than or equal to the output voltage Vout, the intermediate voltage Vm is equal to the output voltage. Vout plus a voltage difference ΔV as small as possible, the so-called voltage difference ΔV as small as possible means: (Vout + ΔV) < Vin_max, for example ΔV = 0.1V; and when the input voltage Vin is greater than or equal to the output voltage Vout, The intermediate voltage Vm is equal to the input voltage Vin plus the voltage difference ΔV, which can be expressed as follows: Vm=Vout+ΔV and (Vout+ΔV)<Vin_max, if Vm=Vin+ΔV, if Vin>Vout

Figure 3 shows the most energy-saving way, but the invention is not limited thereto. When the input voltage Vin is greater than the output voltage Vout, the intermediate voltage Vm does not have to be equal to the input voltage Vin plus the voltage difference ΔV, for example It can be a single- or multi-step step shape as shown in Figure 4 or Figure 5; comparing Figure 4 or Figure 5 with Figure 2 still saves energy. Even in the section where the input voltage Vin is larger than the output voltage Vout, the intermediate voltage Vm may be any other irregular pattern, as shown in FIG.

The hardware embodiment of the above embodiments is as shown in FIG. 7. In addition to the voltage regulating circuit 10 and the linear voltage stabilizing circuit 20, an intermediate voltage (Vm) control circuit 30 is provided. The Vm control circuit 30 receives the input voltage Vin. The indicator signal (Vin indicator, hereinafter referred to as the Vin indicator) and the Vout indicator (hereinafter referred to as the Vout indicator), or the preset reference signal, and the intermediate voltage Vm are adjusted according to the above signal. The Vin indicator may be, for example, a divided voltage of the input voltage Vin, or a current signal after the input voltage Vin is converted into a current, or may be a multiple or a fractional value of the voltage dividing or current signal, or may be the voltage Vin itself. The Vout indicator is also true. The preset reference signal can be a constant, and the setting method is described later.

In view of the desired Vm pattern, the circuit of FIG. 7 has various implementations on the hardware. For example, the Vm pattern of FIG. 4 can be implemented, for example, by the hardware circuit of FIG. 8, wherein the voltage adjustment circuit 10 is assumed to be The boost converter circuit (Boost Converter) controls the operation of the power switch by the boost control circuit 11 according to the comparison of the feedback signal FB1 and the reference voltage Boost_REF to determine the intermediate voltage Vm, and the linear regulator circuit 20 is a low-dropout regulator circuit. (LDO, Low Drop-Out), the LDO control circuit 21 controls the operation of the power switch based on the comparison of the feedback signal FB2 with the reference voltage LDO_REF to determine the output voltage Vout. The Vm control circuit 30 includes a comparator 31 and a selection circuit 35. The comparator 31 compares the Vin index with the Vout indicator or compares the Vin index with a preset reference signal. Based on the output of the comparator 31, the selection circuit 35 selects one of the two reference voltages REF1, REF2 as the reference voltage Boost_REF of the boost control circuit 11. Referring to FIG. 8 and FIG. 4, it is assumed that the input voltage Vin varies between 2.5 and 4.8 V, and the required output voltage Vout is 4.6 V. When the selection circuit 35 selects one of the two reference voltages REF1, REF2, the intermediate voltage Vm Equal to 4.6V plus a voltage difference ΔV (eg, 0.1V) as small as possible. When the selection circuit 35 selects the other of the two reference voltages REF1, REF2, the intermediate voltage Vm is equal to 4.8V plus the voltage difference ΔV.

As can be seen from the above, in the eighth figure, the function of the comparator 31 is to determine when the intermediate voltage Vm jumps to the next stage. If the positive input terminal of the comparator 31 is "preset constant reference signal", the preset reference signal It should correspond to the Vin voltage when the voltage Vm is skipped in Fig. 4. In the present embodiment, if the Vin index /Vin = α, the preset reference signal = α‧ (4.6V).

FIG. 9 shows another hardware embodiment of the present invention, in which the voltage regulating circuit 10 and the linear voltage stabilizing circuit 20 are omitted, but it is also assumed that the voltage regulating circuit 10 is a boost converting circuit and the linear voltage stabilizing circuit 20 is a low voltage drop. Regulator circuit. This embodiment corresponds to the Vm pattern of FIG. 5, and the Vm control circuit 30 includes a plurality of comparators 31-33, a logic circuit 34, and a selection circuit 35, wherein the comparators 31-33 respectively reference the Vin index and the constant preset reference. After the signal 1 is compared with the preset reference signal 3, the comparison result is integrated by the logic circuit 34, and it is determined which one of REF1~REF4 should be selected by the selection circuit 35 as the reference voltage Boost_REF. The number of the comparator and the reference voltage in this embodiment is only an example, and may be determined according to the desired number of Vm pattern steps; the preset reference signal 1 to the preset reference signal 3 are set in the same manner as the previous embodiment. It should correspond to the Vin voltage at the time of the voltage Vm stepping in Fig. 5, respectively.

Fig. 10 shows another embodiment of the present invention, and this embodiment corresponds to the Vm pattern of Fig. 3. The Vm control circuit 30 includes a first voltage-to-current circuit 301, a second voltage-to-current circuit 302, a subtraction circuit 303, a current-to-voltage circuit 304, and an addition circuit 305. When Vin < Vout, VREF is used as a reference voltage in the voltage regulating circuit 10, and this reference voltage is such that the intermediate voltage Vm output from the voltage regulating circuit 10 is equal to 4.6 V plus the voltage difference ΔV. As shown, the first voltage-to-current circuit 301 and the second voltage-to-current circuit 302 convert the Vin indicator and the Vout indicator into current signals, respectively; of course, if the Vin indicator and the Vout indicator are not voltage signals, the current signal is already present. The first voltage to current circuit 301 and the second voltage to current circuit 302 may not be needed. The subtraction circuit 303 subtracts the current signal obtained by the conversion of the Vin index from the current signal obtained by the Vout conversion, but outputs zero if the difference is negative. The current-to-voltage circuit 304 converts the difference into a voltage and adds it to the reference voltage VREF to obtain a desired reference voltage Boost_REF. The reference voltage Boost_REF can generate the Vm pattern of FIG. When Vm=4.6V+ΔV; when Vin>Vout, Vm=Vin+ΔV.

More specific circuits of FIG. 10 can be implemented in various ways. For example, in FIG. 11, in this embodiment, an enable switch SW1 is further provided, and the Vm control circuit 30 can be flexibly determined according to the signal EN. The signal EN can be an external control signal or from any source. When the enable switch SW1 is turned on, if Vin>Vout, the switch SW2 is turned on, the current of the IR1 flows through the resistor RS1, and the current of the IR3 flows through the resistor RS3, where IR3=(Vin−Vout)/RS1. The voltage across IR3×RS3 is generated on the resistor RS3 and superimposed on the reference voltage VREF, that is, Boost_REF=VREF+IR3×RS3. When Vin < Vout, the switch SW2 is not turned on, IR3 is 0, and Boost_REF = VREF.

In the embodiment of Fig. 11, the value of ΔV can be arbitrarily set; the description is as follows.

Vm=FB1×(RB1+RB2)/RB1

=(Boost_REF)×(RB1+RB2)/RB1

=(VREF+IR3×RS3)×(RB1+RB2)/RB1

=[VREF+(Vin-Vout)×RS3/RS1]×(RB1+RB2)/RB1

Vout=FB2×(RB1+RB2/K)/RB1

=(VREF)×(RB1+RB2/K)/RB1

Therefore, if ΔV is to be set to 0.1V, it can be achieved by appropriately arranging the resistance values of the respective resistors, for example, setting K to RB2/(RB2-0.1×RB1), and arranging the resistance values of the resistors RS1 to RS3.

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, in various embodiments, other circuits or components that do not affect the main function may be interposed, such as an interpolable proportional circuit, an analog-to-digital converter, and a digital analog converter in FIG. 10; for example, a first-stage voltage regulation The circuit is not limited to a boost converter circuit, but may be other switched voltage conversion circuits. Therefore, the scope of the invention should be construed as covering the above and all other equivalents.

10. . . Voltage regulation circuit

11. . . Boost control circuit

20. . . Linear regulator circuit

twenty one. . . LDO control circuit

30. . . Intermediate voltage control circuit

31,32,33. . . Comparators

34. . . Logic circuit

35. . . Selection circuit

301. . . First voltage to current circuit

302. . . Second voltage to current circuit

303. . . Subtraction circuit

304. . . Current to voltage circuit

305. . . Addition circuit

RB1, RB2, RB2/K, RS1, RS2, RS3. . . resistance

SW1, SW2. . . switch

Figure 1 shows a schematic circuit diagram of a prior art two-stage voltage regulator circuit.

Fig. 2 shows the relationship between the input voltage Vin, the intermediate voltage Vm, and the output voltage Vout in the prior art.

Figures 3 to 6 show several embodiments of the present invention in which the relationship between the input voltage Vin, the intermediate voltage Vm, and the output voltage Vout is displayed.

Figure 7 shows an adaptive two-stage voltage regulator circuit of the present invention in a schematic circuit diagram.

Fig. 8 exemplifies a hardware implementation corresponding to Fig. 4.

Fig. 9 exemplifies a hardware implementation corresponding to Fig. 5.

Fig. 10 exemplifies a hardware implementation corresponding to Fig. 3.

Figure 11 illustrates a more specific implementation of the circuit of Figure 10 by way of example.

10. . . Voltage regulation circuit

20. . . Linear regulator circuit

30. . . Intermediate voltage control circuit

Claims (13)

An adaptive two-stage voltage regulator circuit includes: a voltage regulating circuit that generates an intermediate voltage (Vm) according to an input voltage (Vin), wherein the input voltage is less than or equal to a maximum value (Vin_max); a linear regulator a circuit that generates an output voltage (Vout) according to the intermediate voltage; and an intermediate voltage control circuit that receives (1) an indicator signal related to the input voltage, and one of: (2a) an indicator signal related to the output voltage , or (2b) the preset first reference signal, and adjust the intermediate voltage according to the received signal, wherein "the indicator signal about the input voltage" and "the indicator signal about the output voltage or the preset first reference signal" are determined. a second reference signal, and the second reference signal is supplied to the voltage regulating circuit such that when the input voltage is less than or equal to the output voltage: Vm=Vout+ΔV, and (Vout+ΔV)<Vin_max, where ΔV is A voltage difference. The adaptive two-stage voltage regulator circuit of claim 1, wherein the intermediate voltage is a single-order or multi-step step shape when the input voltage is greater than the output voltage. The adaptive two-stage voltage regulator circuit of claim 1, wherein when the input voltage is greater than the output voltage, Vm = Vin + ΔV, wherein ΔV is the voltage difference. The adaptive two-stage voltage regulator circuit of claim 1, wherein the intermediate voltage control circuit comprises: a comparator, the "indicator signal about the input voltage" and the "indicator signal about the output voltage or the preset Comparison of the first reference signal"; The selection circuit determines a second reference signal according to the comparison result of the comparator, and the second reference signal is supplied to the voltage adjustment circuit. The adaptive two-stage voltage regulator circuit of claim 1, wherein the intermediate voltage control circuit comprises: a plurality of comparators for comparing the indicator signal of the input voltage with a plurality of preset reference signals; logic a circuit that integrates the output of the comparator; and a selection circuit that determines a second reference signal based on the output of the logic circuit, and the second reference signal is supplied to the voltage regulation circuit. The adaptive two-stage voltage regulator circuit of claim 1, wherein the intermediate voltage control circuit comprises: a subtraction circuit, wherein the indicator signal related to the input voltage is subtracted from the indicator signal related to the output voltage, and the difference is Timing output difference, when the difference is negative, it does not output or output zero; the conversion circuit converts the positive difference value into a voltage signal; the adding circuit adds the voltage signal converted by the positive difference value to a third reference signal The second reference signal is determined, and the second reference signal is supplied to the voltage regulating circuit to adjust the intermediate voltage. The adaptive two-stage voltage regulator circuit of claim 6, wherein the intermediate voltage control circuit further comprises: a first voltage-to-current circuit and a second voltage-to-current circuit, respectively, respectively, the indicator signals related to the input voltage and The index signal about the output voltage is converted into a current signal, and the subtraction circuit is input. A method for controlling a two-stage voltage stabilizing circuit, comprising: generating an intermediate voltage (Vm) according to an input voltage (Vin), wherein the input voltage is less than or equal to a maximum value (Vin_max); Generating an output voltage (Vout) according to the intermediate voltage; receiving (1) an indicator signal related to the input voltage, and one of: (2a) an indicator signal related to the output voltage, or (2b) a preset first a reference signal; and adjusting the intermediate voltage according to the received signal, wherein the "indicator signal related to the input voltage" and the "indicator signal related to the output voltage or the preset first reference signal" determine a second reference signal, and the second The reference signal is supplied to the voltage regulating circuit such that when the input voltage is less than or equal to the output voltage: Vm = Vout + ΔV, and (Vout + ΔV) < Vin_max, where ΔV is a voltage difference. The control method of the two-stage voltage stabilizing circuit as described in claim 8, wherein the intermediate voltage is a single-order or multi-step step shape when the input voltage is greater than the output voltage. The control method of the two-stage voltage stabilizing circuit according to claim 8, wherein when the input voltage is greater than the output voltage, Vm=Vin+ΔV, wherein ΔV is the voltage difference. The method for controlling a two-stage voltage stabilizing circuit as described in claim 8 wherein the step of adjusting the intermediate voltage comprises: "indicating the signal signal about the input voltage" and "the indicator signal of the output voltage or the preset number" A reference signal is compared; and a second reference signal is determined based on the comparison result of the comparator, and the second reference signal is supplied to the voltage regulating circuit. The method for controlling a two-stage voltage stabilizing circuit as described in claim 9, wherein the step of adjusting the intermediate voltage comprises: subtracting an index signal related to the output voltage from an index signal related to the input voltage, when the difference is positive The output difference is not output or output zero when the difference is negative; Converting the positive difference value into a voltage signal; and adding the voltage signal converted by the positive difference value to a third reference signal to determine the second reference signal, and supplying the second reference signal to the voltage regulating circuit, thereby Adjust the intermediate voltage. The method for controlling a two-stage voltage stabilizing circuit according to claim 9, wherein the step of adjusting the intermediate voltage comprises: converting the index signal about the input voltage and the index signal related to the output voltage to Current signal.