TWM465721U - Bi-directional switching regulator and control circuit thereof - Google Patents

Description

Bidirectional switching power supply and its control circuit

The present invention relates to a bidirectional switching power supply and a control circuit thereof, and particularly to a bidirectional switching power supply and a control circuit thereof capable of effectively controlling a charging current or avoiding collapse of a whole circuit and battery damage.

Please refer to FIG. 1, which shows a schematic diagram of a prior art bidirectional switched power supply. The bidirectional switched power supply 10 can operate in a power supply mode or a charging mode. In the charging mode, the bidirectional switched power supply 10 boosts an input voltage VBUS to an output voltage VSYS via a power stage 11, which is to be lower. The input voltage VBUS is converted to a higher output voltage VSYS. The input terminal BUS generating the input voltage VBUS can be connected to an external power source, and the output terminal SYS generating the output voltage VSYS can be connected to a battery BAT and/or a system load. If the input terminal BUS is connected from an external power source to an external device, it becomes a power supply mode. In the first figure, the same circuit becomes a step-down switching power supply, and the battery BAT will have a higher battery via the power stage 11. The voltage VBAT is converted to a lower input voltage VBUS and supplies power to an external device connected to the input BUS. In general, a current control switch M1 is provided between the output terminal SYS and the battery BAT.

The power stage 11 includes an upper bridge switch S2, a lower bridge switch S3, and an inductor L. The three components are commonly connected to a switching node LX. In the charging mode, the external power supply current flows through the inductor L and the upper bridge switch S2 to the output terminal SYS where the output voltage VSYS is located. In the case where the output SYS needs to be a USB port, this prior art is not applicable because the charge generated by the hot plug operation may damage the battery BAT, and if the battery voltage VBAT is too low, the output voltage VSYS is also affected. The system load may not work properly. In addition, there is no connection In the case of a battery BAT, if a short circuit occurs at the battery end (the node where the VBAT is located), the power stage 11 will continue to operate, causing the entire power supply to crash, and excessive current may burn the circuit. Moreover, if the voltage difference between the output voltage VSYS and the battery voltage VBAT is too high, the energy consumption is too high; however, if there is no proper voltage difference between the output voltage VSYS and the battery voltage VBAT, the battery BAT will not be charged smoothly.

In view of this, the present invention is directed to the above-mentioned prior art deficiencies, and proposes a bidirectional switching power supply and a control circuit thereof that can effectively control the charging current or avoid the collapse of the entire circuit and battery damage.

One of the purposes of this creation is to provide a two-way switching power supply.

Another object of the present invention is to provide a control circuit for a bidirectional switched power supply.

For the above purposes, in one of the points of view, the present invention provides a bidirectional switching power supply for converting an input voltage provided at an input to an output voltage at an output in a charging mode, or Converting the output voltage of the output to the input voltage of the input terminal in the power supply mode, the bidirectional switching power supply includes: a power stage coupled between the input end and the output end; an operation circuit, Generating an operation signal for controlling the operation of the power stage, and determining whether to operate in a charging mode or a power supply mode according to a mode control signal; and a power path management circuit having one end electrically connected to the output end and the other end being used for Electrically connected to a battery to control the charging current of the battery to the output terminal, the power path management circuit includes a power path switch electrically connected between the output terminal and the battery; and a power path controller for Controlling the power path switch to control the charging current, wherein the operating circuit is based on the information about the output voltage or the voltage of the battery The operation information and the information about the charging current are generated to generate the operation signal, so that (1) the voltage difference between the output voltage and the battery voltage is ICHG*R, wherein ICHG is the charging current, and R is the The on-resistance of the power path switch when fully turned on; or (2) the output voltage is determined by the battery voltage and ICHG*R The sum, or a preset voltage level, is determined by the larger order between the two.

In another opinion, the present invention also provides a control circuit for a bidirectional switched power supply, controlling a power stage to convert an input voltage provided by an input to an output voltage at an output in the charging mode. Or converting the output voltage of the output to the input voltage of the input terminal in the power supply mode, the control circuit includes: an operation circuit for generating an operation signal, thereby controlling the operation of the power level, and controlling the signal according to a mode Determining operation in a charging mode or a power supply mode; and a power path management circuit having one end electrically connected to the output end and the other end electrically connected to a battery to control a charging current of the output terminal to the battery, The power path management circuit includes a power path switch electrically connected between the output terminal and the battery, and a power path controller for controlling the power path switch to control the charging current, wherein the operating circuit is configured according to the output The information about the voltage or the information about the voltage of the battery, and the related information of the charging current, Signaling such that (1) the voltage difference between the output voltage and the battery voltage is ICHG*R, wherein ICHG is the charging current, and R is the on-resistance when the power path switch is fully turned on; or (2) The output voltage is determined by the sum of the battery voltage and the ICHG*R, or a predetermined voltage level, which is relatively large.

In a preferred embodiment, when the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the predetermined voltage level, the power path switch is turned off.

In a preferred embodiment, the bidirectional switched power supply charges the battery in another path when the power path switch is turned off.

In a preferred embodiment, when the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the preset voltage level, the power path controller operates the power path switch to Linear area.

In a preferred embodiment, the operating circuit includes: a control signal generating circuit, generating a control signal according to the information about the output voltage or related information of the voltage of the battery, and related information of the charging current; A power switch control circuit generates the operation signal according to the control signal.

In a preferred embodiment, the control signal generating circuit includes: a first error amplifier, comparing information about the output voltage or related information of the voltage of the battery with a first reference signal; and a second The error amplifier compares the information about the charging current with a second reference signal.

In a preferred embodiment, the control signal generating circuit includes: a first error amplifier, the related information of the output voltage or the related information of the voltage of the battery and a first reference signal, or the preset voltage Comparing the related information of the level; a second error amplifier comparing the related information of the charging current with a second reference signal; a comparator for determining a relative relationship between the output voltage and the preset voltage level; And a multiplexer, according to the judgment result of the comparator, selecting to provide the first reference signal or the related information of the preset voltage level to the first error amplifier.

In a preferred embodiment, the bidirectional switching power supply or its control circuit further includes a comparator for determining a relative relationship between the battery voltage and the preset voltage level.

The details of the creation, the technical content, the features and the effects achieved by the present invention are more easily explained by the detailed description of the specific embodiments.

[study]

10‧‧‧Learning two-way switching power supply

11‧‧‧Learning power level

12‧‧‧Custom drive circuit

13‧‧‧Learning error amplifier

Comp‧‧‧Chinese error signal

M1‧‧‧Knowledge load switch

[this creation]

20‧‧‧Two-way switching power supply

21‧‧‧Power level

22‧‧‧Operating circuit

221‧‧‧Control signal generation circuit

222‧‧‧Power switch control circuit

224‧‧‧ Comparator

226‧‧‧Multiplexer

227‧‧‧ comparator

228‧‧‧current source circuit

23‧‧‧First voltage detecting component

24‧‧‧Control signal generation circuit

25‧‧‧Power Path Management Circuit

251‧‧‧Power Path Controller

27‧‧‧Second voltage detecting component

28‧‧‧ Third voltage detecting component

40‧‧‧Control circuit

BAT‧‧‧Battery

BUS‧‧‧ input

CL1, CL3‧‧‧ control signals

EA1, EA3‧‧‧ error amplifier

EN‧‧‧Enable control terminal

FB1~FB3‧‧‧Response signal

ICHG‧‧‧Charging current

L‧‧‧Inductance

LX‧‧‧ switching node

MC‧‧‧ mode control signal

Q1‧‧‧Optoelectronics

Q2‧‧‧ adjustable polarity transistor

R‧‧‧ On-resistance

RS‧‧‧ sense resistor

S1‧‧‧Power path switch

S2‧‧‧Upper Bridge Switch

S3‧‧‧Bridge switch

SD1‧‧‧ Schottky diode

SL1, SL1'‧‧‧ first operation signal

SL2‧‧‧second operation signal

SYS‧‧‧ output

VA‧‧‧Preset voltage level

VBAT‧‧‧ battery voltage

VBUS‧‧‧ input voltage

Vref1, Vref3‧‧‧ reference signal

VSYS‧‧‧ output voltage

Figure 1 shows a schematic diagram of a prior art bidirectional switched power supply.

Fig. 2 is a view showing a bidirectional switching power supply of an embodiment of the present invention.

Figures 3A-3B show an embodiment of the operational circuitry of the present invention.

Figure 3C shows an embodiment of the first voltage detecting element and the second voltage detecting element.

Figure 4 shows the relationship between the output voltage VSYS and the battery voltage VBAT.

Figure 5 shows the relationship between the output voltage VSYS and the battery voltage VBAT and the preset voltage level VA.

Fig. 6 shows another embodiment of the operational circuit of the present creation.

Figures 7-8 show the control method when the battery voltage VBAT is lower than the preset voltage level VA.

Figure 9 is a diagram showing a bidirectional switched power supply of another embodiment of the present invention.

Figures 10A-10D show several other embodiments of a power path switch.

Figure 11 shows another embodiment of the power stage that was created during the boost operation.

The above and other technical contents, features and effects of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. The drawings in this creation are all schematic representations, and are intended to represent the functional interaction between the various devices and components. The shapes, thicknesses, and widths are not drawn to scale.

Please refer to FIG. 2, which shows a schematic diagram of a bidirectional switched power supply according to an embodiment of the present invention. The bidirectional switching power supply 20 can convert an input voltage VBUS provided by an input terminal BUS into an output voltage VSYS at an output terminal SYS, or a battery voltage VBAT of a battery BAT (or an output voltage VSYS of the output terminal SYS). Converted to the voltage at the input BUS. The input terminal BUS can be coupled to an external power source to receive external power supply or coupled to an external device to supply power to the external device. The bidirectional switched power supply 20 includes a power stage 21, an operating circuit 22, and a power path management circuit 25. The power stage 21 includes an upper bridge switch S2, a lower bridge switch S3, and an inductor L. One end of the upper bridge switch S2 is electrically connected to the output terminal SYS and the other end thereof is electrically connected to a switching node LX. One end of the lower bridge switch S3 is electrically connected to the switching node LX and the other end thereof is electrically connected to the ground. One end of the inductor L is electrically connected to the switching node LX and the other end thereof is electrically connected to the input terminal BUS. The upper bridge switch S2 and the lower bridge switch S3 may be, for example but not limited to, NMOS transistors or PMOS transistors. The operation circuit 22 is configured to generate a first group of operation signals SL1 and SL1' for controlling the upper bridge switch S2 and the lower bridge switch S3, thereby switching the on and off of the upper bridge switch S2 and the first lower bridge switch S3, wherein the operation signal SL1 And the SL1' is, for example but not limited to, a pulse width modulation signal that is substantially complementary to each other (in order to avoid the shoot-through of the two switches being simultaneously turned on, the operation signals SL1 and SL1' may be arranged to be substantially complementary but for some time. It is not dead-time, which is well known to those skilled in the art and will not be described in detail herein. operating The circuit 22 is based on the information about the output voltage VSYS (for example, the output voltage VSYS itself or its voltage division signal), the battery voltage VBAT related information (such as the battery voltage VBAT itself or its voltage division signal), and/or the battery BAT The information related to the charging current ICHG generates the operation signals SL1 and SL1'; how the operation circuit 22 generates the operation signals SL1 and SL1' is detailed later. The bidirectional switching power supply 20 can selectively include the first voltage detecting component 23 and the second voltage detecting component 27 to detect the output voltage VSYS and the battery voltage VBAT; if the levels of the voltages are processed by the circuit, Then, the first voltage detecting component 23 and the second voltage detecting component 27 can be omitted.

For example, the operation circuit 22 can determine the charging mode according to a mode control signal MC (that is, boosting the power supply from the external power source at the input terminal BUS to the output terminal SYS) or the power supply mode (ie, the self-battery voltage VBAT pair is located at the input terminal BUS). The external device is step-down power supply). The mode control signal MC has various generation modes, for example, it can be input by an external circuit, input by a user, or judged according to the characteristics of the input terminal BUS. For example, it can be judged that the input terminal BUS is an absorption current or a supply current. If the current is absorbed, it is determined that the input terminal BUS is connected to an external device. If the current is supplied, it is determined that the input terminal BUS is connected to the external power source. Each type of input BUS external connection specification has its corresponding power supply end or charging end judgment mode, and can adopt the corresponding judgment mode according to the actual application condition, or directly accept external control to switch modes. The details of the above judgment methods are not the focus of this case and will not be described here.

One end of the power path management circuit 25 is electrically connected to the output terminal SYS and the other end thereof is electrically connected to the battery BAT. The power path management circuit 25 includes a power path switch S1 and a power path controller 251, wherein the power path switch S1 is electrically connected between the output terminal SYS and the battery BAT. When the input terminal BUS of the embodiment is powered by an external power source, the power supplied by the external power source can charge the battery BAT via the boosting operation of the power stage 21, and the power path controller 251 can control the power path switch S1 to Thereby, the charging current ICHG flowing through the power path switch S1 is controlled.

Please refer to FIG. 3A-3B, which shows a real operation circuit 22 of the present creation. Example. As shown in FIG. 3A, the operation circuit 22 includes a control signal generation circuit 221 and a power switch control circuit 222. The control signal generation circuit 221 is based on the feedback signal FB1 (representing information related to the output voltage VSYS) or FB2 (representing the battery voltage VBAT). The relevant information), and FB3 (representing information related to the charging current ICHG), generate a control signal CL. The power switch control circuit 222 generates the operation signals SL1 and SL1' to control the upper bridge switch S2 and the lower bridge switch S3 based on the control signal CL.

FIG. 3B shows an embodiment of the control signal generating circuit 221. The control signal generating circuit 221 includes error amplifiers EA1 and EA3, wherein the error amplifier EA1 compares the feedback signal FB1 or FB2 with the reference signal Vref1 to generate the control signal CL1, and the error amplifier EA3 compares the feedback signal FB3 with the reference signal Vref3 to generate control. Signal CL3. The control signal CL contains control signals CL1 and CL3. The power switch control circuit 222 generates the operation signals SL1 and SL1' according to the control signal CL, which are generated in various manners and are well known to those skilled in the art and will not be described in detail herein. For example, the power switch control circuit 222 can compare the control signal CL1 with a sawtooth wave signal to generate a fixed frequency pulse width modulation signal, or a fixed pulse width frequency conversion signal, etc., and when the control signal CL3 displays charging. When the current ICHG is insufficient, the power switch control circuit 222 can increase the duty ratio of the fixed frequency pulse width modulation signal or increase the frequency of the fixed pulse width frequency conversion signal. By the loop feedback control mechanism, the output voltage VSYS or the battery voltage VBAT can be adjusted to a desired target value (corresponding to the reference signal Vref1), and the charging current ICHG is adjusted to a desired target value (corresponding to the reference signal Vref3). ).

FIG. 3C shows an embodiment of the first voltage detecting component 23 and the second voltage detecting component 27, wherein the first voltage detecting component 23 and the second voltage detecting component 27 can be, for example, a resistor divider circuit. The upper divided voltage is used as the feedback signal FB1 and the feedback signal FB2.

Please refer to Figure 3B and compare Figure 4 to illustrate the control objectives that the above circuit is intended to achieve. Figure 4 shows the relationship between the output voltage VSYS and the battery voltage VBAT in one of the embodiments. In the present embodiment, the power path controller 251 controls the power path switch S1 to be fully turned on, so the power path switch S1 has the lowest on-resistance, and the output voltage VSYS is Determined by the sum of the battery voltages VBAT and ICHG*R of the battery BAT (as shown by the solid line and the broken line in FIG. 4), wherein ICHG is the charging current through the power path switch S1, and R is the lowest of the power path switch S1. On resistance. Since the voltage drop between the battery voltage VBAT and the output voltage VSYS is the lowest, the energy consumption can be optimally controlled.

It should be noted that when the power path switch S1 is fully turned on and the charging current ICHG is controlled to the target value, since the voltage difference between the output voltage VSYS and the battery voltage VBAT has a controlled relationship, the circuit can be based on the output voltage VSYS and Any of the battery voltages VBAT is used for feedback control, and both the output voltage VSYS and the battery voltage VBAT are feedback-regulated. That is why the error amplifier EA1 described above can compare any one of the feedback signals FB1 or FB2 with the reference signal Vref1 to generate the control signal CL1.

Referring to FIG. 5, the relationship between the output voltage VSYS and the battery voltage VBAT and the preset voltage level VA is shown in another embodiment. In this embodiment, the output voltage VSYS should not be lower than the preset voltage level VA to maintain the system load (see FIG. 2) to obtain the required voltage. In this case, as shown in FIG. 6, the control signal generating circuit 221 may further include a comparator 224 and a multiplexer 226. The comparator 224 is configured to determine a relative relationship between the output voltage VSYS and the preset voltage level VA, one of the input terminals receives the output voltage VSYS or its related signal, and the other input terminal receives the preset voltage level VA or its related signal. . If one of the input terminals of the comparator 224 receives the output voltage VSYS, the other input terminal receives the preset voltage level VA; if one of the input terminals receives the relevant signal of the output voltage VSYS (for example, the feedback signal FB1), according to the feedback The relative proportional relationship between the signal FB1 and the output voltage VSYS, the preset voltage level VA should also be multiplied by the relative proportional relationship before being input to the other input of the comparator 224. When the output voltage VSYS is lower than the preset voltage level VA, the multiplexer 226 selects the preset voltage level VA or its associated signal, and the error amplifier EA1 sets the feedback signal FB1 or FB2 to the preset voltage level VA or its correlation. The signal is compared. The output voltage VSYS can be adjusted to a preset voltage level VA by a loop feedback control mechanism. (If the error amplifier EA1 is receiving the feedback signal FB2, the value of the preset voltage level VA or its associated signal can be adjusted accordingly to compensate for the difference between the output voltage VSYS and the battery voltage VBAT. The pressure difference is ICHG*R. When the output voltage VSYS is not lower than the preset voltage level VA, the multiplexer 226 selects the reference signal Vref1, and the error amplifier EA1 compares the feedback signal FB1 or FB2 with the reference signal Vref1, the mechanism and the 3B and 4th The figure is the same.

Please continue to refer to Figure 5, when the output voltage VSYS is maintained at the preset voltage level VA and the battery voltage VBAT is lower than the preset voltage level VA, since the voltage difference between the output voltage VSYS and the battery voltage VBAT is not equal to the ICHG* R, therefore, the voltage difference between the output voltage VSYS and the battery voltage VBAT cannot be controlled in a controlled relationship by making the power path switch S1 fully conductive and controlling the charging current ICHG to a target value. In this case, please refer to FIG. 7. In a preferred embodiment, the bidirectional switched power supply 20 can further include a comparator 227 and a current source circuit 228 (the comparator 227 and the current source circuit 228 can be, for example, It is disposed within the operating circuit 22 and may also be a separate circuit external to the operating circuit 22). The comparator 227 is configured to determine a relative relationship between the battery voltage VBAT and the preset voltage level VA, one of the input terminals receives the battery voltage VBAT or its related signal, and the other input terminal receives the preset voltage level VA or its related signal. . When the battery voltage VBAT is lower than the preset voltage level VA, the output of the comparator 227 can turn off the power path switch S1 (so that the voltage difference between the output voltage VSYS and the battery voltage VBAT is not affected by the voltage drop of the power path switch S1) In addition, the current source circuit 228 can be selectively turned on (eg, the output of the comparator 227 can be transferred to the enable control terminal EN of the current source circuit 228) to cause the battery BAT to be charged via an additional path. Current source circuit 228 can charge battery BAT, for example, but not limited to, from output SYS or input BUS. When the battery voltage VBAT is higher than the preset voltage level VA, the circuit operates in accordance with the same mechanism as described in the foregoing 3B and FIG. Moreover, when the battery voltage VBAT is lower than the preset voltage level VA, the power path switch S1 can be simply turned off without charging the battery BAT via another path.

Referring to FIG. 8 , in another preferred embodiment, the bidirectional switched power supply 20 may further include a comparator 227 (the comparator 227 may be disposed, for example, within the operating circuit 22 or external to the operating circuit 22 . Independent circuit). As in the embodiment of FIG. 7, the comparator 227 is configured to determine the relationship between the battery voltage VBAT and the preset voltage level VA, and one of the input terminals receives the power. The cell voltage VBAT or its associated signal, the other input receives the preset voltage level VA or its associated signal. When the battery voltage VBAT is lower than the preset voltage level VA, the output of the comparator 227 can be transmitted to the power path controller 251 to control the power path switch S1 to operate in the linear region of the transistor. When the power path switch S1 operates in the linear region, the voltage difference between the output voltage VSYS and the battery voltage VBAT is not equal to ICHG*R, so the output voltage VSYS is not affected by the battery voltage VBAT being too low. When the battery voltage VBAT is higher than the preset voltage level VA, the circuit operates in accordance with the same mechanism as described in the foregoing 3B and FIG.

Referring to FIG. 9, when the bidirectional switching power supply 20 needs to supply power from the external voltage of the input terminal BUS from the battery voltage VBAT, if the feedback control is required, the circuit may further include a third voltage sensing component. 28. The relevant voltage information of the input terminal BUS is detected and transmitted to the operation circuit 22. If the voltage level of the input terminal BUS can be processed by the operation circuit 22, the third voltage sensing element 28 can also be omitted.

In an embodiment, the operating circuit 22, the power path management circuit 25, and the current source circuit 228 may be integrated into a control circuit 40 in whole or in part by integrated circuit fabrication techniques.

Please refer to Figures 10A-10D, which show several other embodiments of the power path switch. The power path switch S1 includes a transistor Q1 (as shown in FIG. 10A) or a transistor Q2 with a variable parasitic diode polarity (as shown in FIG. 10B). In addition, the power path switch S1 may further include a sensing resistor connected to the transistor Q1 (as shown in FIG. 10C) or to the transistor Q2 of the adjustable parasitic diode polarity (as shown in FIG. 10D). ). In the embodiment shown in FIGS. 10A and 10C, the parasitic diode anode of the transistor Q1 is electrically connected to the battery BAT, and the cathode thereof is electrically connected to the output terminal SYS, so that when the output voltage VSYS of the output terminal SYS is higher than the battery BAT At the battery voltage VBAT, the parasitic diode of the transistor Q1 can block the reverse current flowing from the output terminal SYS to the battery BAT. Alternatively, as shown in FIGS. 10B and 10D, since the polarity direction of the parasitic diode of the transistor Q2 is adjustable, when the output voltage VSYS of the output terminal SYS is higher than the battery voltage VBAT of the battery BAT, in order to prevent current from flowing backward The anode-cathode direction of the parasitic diode can be opposite to the direction of current reverse flow; for example, when the output voltage VSYS of the output terminal SYS is lower than the battery of the battery BAT When the voltage is VBAT and in order to prevent current from flowing downstream from the battery BAT to the output terminal SYS (for example, when the operation of the bidirectional switching power supply 20 is to be stopped), the anode-cathode direction of the parasitic diode is opposite to the direction in which the current flows downstream. . In this way, the function of protection and control of the circuit and the battery BAT can be provided.

Referring to FIG. 11, when the bidirectional switching power supply 20 only needs to perform the unidirectional boosting operation, the upper bridge switch S2 in the power stage 21 can be replaced by a Schottky diode SD1, as shown in FIG. Shown.

The features and advantages of this creation are: first, the output voltage VSYS and the battery voltage VBAT have the best voltage difference relationship; second, even if the battery voltage VBAT is too low, it will not affect the output voltage VSYS; third, the power supply The path switch S1 is properly controlled. When the voltage difference between the output voltage VSYS and the battery voltage VBAT is too large, the power path switch S1 is turned off or operates in the linear region, so that the power stage 21 does not work continuously and the entire power supply is caused. The problem of crashing.

The present invention has been described above with reference to the preferred embodiments, and the above description is only for the purpose of making the present invention easy to understand the content of the present invention, and is not intended to limit the scope of the present invention. In the same spirit of the creation, those skilled in the art can think of various equivalent changes. For example, in the circuit of each embodiment shown, components that do not affect the main meaning of the signal, such as other switches, may be inserted; for example, the power path switch S1, the upper bridge switch S2, and the lower bridge switch S3 may be PMOS or NMOS, and the circuit The corresponding transformation can be made. For another example, the input and output signs of the error amplifier or comparator can be interchanged, and only need to be modified in the circuit. All of these can be derived from the teachings of this creation. Therefore, the scope of this creation should cover all of the above and all other equivalent changes. In addition, any implementation of the present invention does not necessarily have to achieve all of the objects or advantages, and therefore, the scope of the claimed patent should not be limited thereto.

20‧‧‧Two-way switching power supply

21‧‧‧Power level

22‧‧‧Operating circuit

23‧‧‧First voltage detecting component

25‧‧‧Power Path Management Circuit

251‧‧‧Power Path Controller

27‧‧‧Second voltage detecting component

40‧‧‧Control circuit

BAT‧‧‧Battery

BUS‧‧‧ input

FB1~FB3‧‧‧Response signal

ICHG‧‧‧Charging current

L‧‧‧Inductance

LX‧‧‧ switching node

MC‧‧‧ mode control signal

S1‧‧‧Power path switch

S2‧‧‧Upper Bridge Switch

S3‧‧‧Bridge switch

SL1, SL1’‧‧‧ first operation signal

SL2‧‧‧second operation signal

SYS‧‧‧ output

VBAT‧‧‧ battery voltage

VBUS‧‧‧ input voltage

VSYS‧‧‧ output voltage

Claims (16)

A bidirectional switching power supply for converting an input voltage provided by an input terminal into an output voltage to an output terminal in a charging mode, or converting an output voltage of the output terminal to the input terminal in a power supply mode The input voltage, the bidirectional switching power supply includes: a power stage coupled between the input end and the output end; an operating circuit that generates an operation signal to control the operation of the power level, and according to The mode control signal determines whether to operate in the charging mode or the power supply mode; and a power path management circuit, one end of which is electrically connected to the output end, and the other end is electrically connected to a battery to control the output end to charge the battery Current, the power path management circuit includes a power path switch electrically connected between the output terminal and the battery; and a power path controller for controlling the power path switch to control the charging current, wherein the operating circuit Generating information related to the output voltage or related information of the voltage of the battery, and related information of the charging current Operating the signal such that (1) the voltage difference between the output voltage and the battery voltage is ICHG*R, wherein ICHG is the charging current, and R is the on-resistance when the power path switch is fully turned on; or (2) The output voltage is determined by the sum of the battery voltage and the ICHG*R, or a predetermined voltage level, which is relatively large. The bidirectional switched power supply of claim 1, wherein the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the preset voltage level, the power path switch shut down. The bidirectional switched power supply of claim 2, wherein when the power path switch is turned off, the bidirectional switched power supply is powered by another path. The pool is charged. The bidirectional switching power supply device of claim 1, wherein the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the preset voltage level, the power path control The power path switch operates in a linear region. The bidirectional switching power supply device of claim 1, wherein the operation circuit comprises: a control signal generating circuit, based on the information about the output voltage or related information of the voltage of the battery, and the charging current Related information, generating a control signal; and a power switch control circuit for generating the operation signal according to the control signal. The bidirectional switched power supply device of claim 5, wherein the control signal generating circuit comprises: a first error amplifier, and the related information of the output voltage or the related information of the voltage of the battery is first The reference signal is compared; and a second error amplifier compares the information about the charging current with a second reference signal. The bidirectional switched power supply device of claim 5, wherein the control signal generating circuit comprises: a first error amplifier, and the related information of the output voltage or the related information of the voltage of the battery is first Comparing the reference signal or the related information of the preset voltage level; a second error amplifier comparing the related information of the charging current with a second reference signal; a comparator for determining the output voltage and the preset Corresponding relationship between voltage levels; and a multiplexer, according to the judgment result of the comparator, selecting to provide related information of the first reference signal or the preset voltage level to the first error amplifier. The bidirectional switching power supply device of claim 1, further comprising a comparator for determining a relative relationship between the battery voltage and the preset voltage level. A control circuit for a bidirectional switched power supply, controlling a power stage to convert an input voltage provided by an input to an output voltage at an output in a charging mode, or in an output mode in a power supply mode The output voltage is converted into an input voltage of the input terminal, and the control circuit comprises: an operation circuit for generating an operation signal, thereby controlling the operation of the power level, and determining the operation in the charging mode or the power supply mode according to a mode control signal; And a power path management circuit, one end of which is electrically connected to the output end, and the other end is electrically connected to a battery to control a charging current of the output end of the battery, the power path management circuit includes a power path switch, and Connected between the output terminal and the battery; and a power path controller for controlling the power path switch to control the charging current, wherein the operating circuit is related to the output voltage or the voltage of the battery according to the output voltage Information, and information about the charging current, to generate the operation signal, so that (1) the output voltage The voltage difference between the battery voltages is ICHG*R, wherein ICHG is the charging current, R is the on-resistance when the power path switch is fully turned on; or (2) the output voltage is determined by the battery voltage and ICHG*R The sum of the voltages, or a preset voltage level, is determined by the higher level between the two. The control circuit of claim 9, wherein the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the predetermined voltage level, the power path switch is turned off. The control circuit of claim 10, wherein the bidirectional switched power supply charges the battery in another path when the power path switch is turned off. The control circuit of claim 9, wherein the output voltage is determined by the preset voltage level, and when the battery voltage is lower than the preset voltage level, the power path controller enables the power source The path switch operates in the linear region. The control circuit of claim 9, wherein the operation circuit comprises: a control signal generating circuit, based on the information about the output voltage or related information of the voltage of the battery, and related information of the charging current, a control signal; and a power switch control circuit for generating the operation signal according to the control signal. The control circuit of claim 13, wherein the control signal generating circuit comprises: a first error amplifier, and comparing information about the output voltage or related information of the voltage of the battery with a first reference signal; And a second error amplifier, the related information of the charging current is compared with a second reference signal. The control circuit of claim 13, wherein the control signal generating circuit comprises: a first error amplifier, the related information of the output voltage or the related information of the voltage of the battery and a first reference signal, or Comparing the related information of the preset voltage level; a second error amplifier comparing the related information of the charging current with a second reference signal; a comparator for determining the output voltage and the preset voltage level And a multiplexer, according to the judgment result of the comparator, selecting to provide related information of the first reference signal or the preset voltage level to the first error amplifier. The control circuit of claim 9 further includes a comparator for determining a relative relationship between the battery voltage and the predetermined voltage level.