TWM467251U - 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 more particularly to a bidirectional switching power supply capable of electrically connecting at least two batteries having different battery capacities by using a single power level and a control circuit thereof.

Please refer to FIG. 1, which shows a schematic diagram of a prior art bidirectional switched power supply. Conventionally, if the bidirectional switched power supply 10 is to charge at least two batteries BATA and BATB having different battery capacities, the bidirectional switched power supply 10 needs to be respectively connected to the corresponding first power from a single supply terminal BUS. The first power stage 11A and the second power stage 11B respectively have a corresponding first output end OUTA and second output end OUTB. The first output terminal OUTA and the second output terminal OUTB are electrically connected to the first battery BATA and the second battery BATB, respectively. 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 supplies the supply voltage VBUS provided by the supply terminal BUS to the second power stage 11A and the second power stage 11B, respectively. The buck is converted into a first output voltage VOUTA at the first output terminal OUTA and a second output voltage VOUB at the second output terminal OUTB, that is, the higher supply voltage VBUS is converted into a lower first output voltage VOUTA and the first Two output voltages VOUTB. Accordingly, the first battery BATA and the second battery BATB can be charged separately. When the supply BUS is not connected to the power supply, but When connected to a device to be charged, the bidirectional switched power supply 10 can be connected to the first output terminal OUTA or the second output terminal OUTB electrically connected to the first battery BATA or the second battery BATB (alternative but not At the same time) supply power to the supply side BUS, this is the power supply mode. In the power supply mode, the same circuit shown in FIG. 1 will become a boost type switching power supply, and the first battery BATA or the second battery BATB will be respectively via the first power stage 11A or the second power stage 11B. The lower first battery voltage VBATA or the second battery voltage VBATB is boosted to a higher supply voltage VBUS and supplies power to the supply BUS.

The first power stage 11A includes an upper bridge switch S2A, a lower bridge switch S3A and an inductor LA, and is commonly connected to a switching node LXA. The second power stage 11B includes an upper bridge switch S2B, a lower bridge switch S3B and an inductor LB, and is commonly connected to a switching node LXB. In order to protect one of the power supplies connected to the supply side BUS, the bidirectional switched power supply 10 can be provided with power protection transistors S1A and S1B between the supply side BUS and the power protection nodes MIDA and MIDB and the upper bridge switches S2A and S2B, respectively. The transistor S1A is connected to the upper bridge switch S2A and the lower bridge switch S3A by a control circuit (not shown), and the transistor S1B and the upper bridge switch S2B and the lower bridge switch S3B are controlled by another control circuit (not shown). ). In this prior art architecture, each of the batteries needs to be electrically connected to their respective power levels, thus resulting in a large number of components, which not only causes the overall bulk of the bidirectional switched power supply 10 to be bulky but also increases manufacturing costs.

In view of this, the present invention is directed to the above-mentioned prior art deficiencies, and proposes a bidirectional switching power supply device and a control circuit thereof that can electrically connect at least two batteries having different battery capacities by using a single power level.

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.

In order to achieve the above purpose, in one aspect, the present invention provides a bidirectional switching power supply for converting a supply voltage supplied from a supply terminal to an output voltage to an output in a charging mode. And in a power supply mode, the output terminal is powered to the supply end, the bidirectional switched power supply includes: a single power stage coupled between the supply end and the output end for Performing power conversion between the two; an operation circuit for generating an operation signal for controlling the power level; a power path management circuit coupled to the output terminal, the power path management circuit comprising: a first power path switch One end is coupled to the output end, the other end of the first battery is coupled to a first battery, the first battery has a first battery voltage, and a second power path switch is coupled to the output end. The other end of the battery can be coupled to a second battery, the second battery has a second battery voltage, and a power path controller for controlling the power path management circuit.

In a preferred embodiment, the bidirectional switched power supply is controlled by one of the following methods or a combination thereof: (1) the output voltage is between the first battery voltage and the second battery voltage The larger the level is determined by adding a total of the safety difference; (2) the output voltage is determined by the level between the first battery voltage and the second battery voltage; (3) the power source The path controller controls to completely turn on the first or second power path switch corresponding to the larger level between the first battery voltage and the second battery voltage, and the other of the first or second power path switches Or operating in a linear mode; or (4) when the difference between the output voltage and the first battery voltage or the second battery voltage is less than one When the voltage level is set, the corresponding first or second power path switch is turned off.

In another aspect, the present invention also provides a control circuit for a bidirectional switched power supply for controlling a power stage to convert a supply voltage provided by a supply to an output voltage in a charging mode. An output terminal is further supplied to the supply terminal from the output terminal in a power supply mode, the control circuit includes: an operation circuit for generating an operation signal for controlling the power level; and a power path management circuit, The power path management circuit includes: a first power path switch, one end of which is coupled to the output end, and the other end of which is coupled to a first battery, the first battery has a first a battery voltage; and a second power path switch, one end of which is coupled to the output end, the other end of which is coupled to a second battery, the second battery has a second battery voltage, wherein the first power source The path switch and the second power path switch jointly couple the first battery and the second battery to the same output end; and a power path controller for controlling the power path management Road.

In a preferred embodiment, the operating circuit includes: a comparator that compares the level of the first battery voltage or its associated signal with the second battery voltage or its associated signal to generate a comparison result. a multiplexer, according to the comparison result, determining to select the output of the first battery voltage or its associated signal or the second battery voltage or its related signal is relatively large; an adder, receiving the multi Outputting the multiplexer and summing the output of the multiplexer with the safety difference or its associated signal to produce a total result; and an error amplifier or comparator comparing the summed result with a reference voltage Generating a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal.

In a preferred embodiment, the operating circuit includes: a comparator for comparing the position of the first battery voltage or its associated signal with the second battery voltage or its associated signal a multiplexer to generate a comparison result; a multiplexer, according to the comparison result, determining to select the output of the first battery voltage or its associated signal or the second battery voltage or a related signal between the two of them; And an error amplifier or comparator, comparing the output of the multiplexer with a reference voltage to generate a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal.

In a preferred embodiment, the operating circuit further includes: a circuit for determining whether the difference between the output voltage and the first battery voltage or the second battery voltage is less than a predetermined voltage level.

In a preferred embodiment, the bidirectional switching power supply further includes a power protection transistor, one end of which is electrically connected to the supply end, and the other end of which is electrically connected to the power stage for protecting the supply end. Connected to a power supply, the power protection transistor has a parasitic diode whose direction blocks the reverse current flowing from the power stage to the supply terminal.

In a preferred embodiment, the first or second power path switch includes a transistor having a parasitic diode that is blocked from flowing from the output to the first or second Battery current.

In a preferred embodiment, the first or second power path switch comprises A tunable parasitic diode transistor having a polarity-adjustable one parasitic diode.

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

11A‧‧‧The first power level

11B‧‧‧Knowledge second power stage

OUTA‧‧‧Knowledge first output

OUTB‧‧‧Knowledge second output

VOUTA‧‧‧I know the first output voltage

VOUTB‧‧ ‧known second output voltage

[this creation]

20‧‧‧Two-way switching power supply

21‧‧‧Power level

22‧‧‧Operating circuit

221‧‧‧Multiplexer

222‧‧‧Adder

223‧‧‧Error amplifier

224‧‧‧ Comparator

225‧‧‧Error amplifier

226‧‧‧ comparator

228‧‧‧ Pulse Width Modulation (PWM) Signal Generator

229‧‧‧ drive circuit

23‧‧‧Power Path Management Circuit

24‧‧‧Power Path Controller

30‧‧‧Control circuit

BATA‧‧‧First battery

BATB‧‧‧second battery

BUS‧‧‧Supply

L, LA, LB‧‧‧ inductance

LX, LXA, LXB‧‧‧ switching nodes

MID, MIDA, MIDB‧‧‧ power protection node

RA‧‧‧First resistance

RB‧‧‧second resistance

S1, S1A, S1B‧‧‧ power protection transistor

S2, S2A, S2B‧‧‧ upper bridge switch

S3, S3A, S3B‧‧‧ lower bridge switch

S4A, S4C‧‧‧ first power path switch

S4B, S4D‧‧‧ second power path switch

SD1‧‧‧ Schottky diode

SL1‧‧‧ operation signal

SLA‧‧‧First switch signal

SLB‧‧‧Second switch signal

SYS‧‧‧ output

SYSA‧‧‧ first output node

SYSB‧‧‧ second output node

VBATA‧‧‧First battery voltage

VBATB‧‧‧second battery voltage

VBUS‧‧‧ supply 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-3E show several other embodiments of the first power path switch and the second power path switch.

Figures 4A-4C show several embodiments of the control scheme of the present creation.

Figures 5A-5B show several embodiments of the power stage that were created in the power mode.

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 switched power supply 20 can operate in a power mode or a charging mode, and the bidirectional switched power supply 20 includes a power stage 21, an operating circuit 22, and a power path management circuit 23. The power stage 21 includes: an upper bridge switch S2, one end of which is electrically connected to a supply end BUS, and the other end of which is electrically connected to a switching node LX; the lower bridge switch S3 is electrically connected to the switching node LX at one end and electrically Connected to the ground; and an inductor L, one end of which is electrically connected to the switching node LX, and the other end of which is electrically connected to an output terminal SYS. 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 the 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 to supply electric energy from the supply side BUS Transfer to the output SYS. Compared with the prior art bidirectional switched power supply 10 (as shown in FIG. 1), the bidirectional switched power supply 20 of the present invention only needs to be powered by a power path. The management circuit 23 can electrically connect at least two batteries from a single output terminal SYS, that is, one end of the power path management circuit 23 is electrically connected to the output terminal SYS and the other end thereof is electrically connected to at least two batteries (ie, the first battery BATA and the second battery) The battery BATB), in this way, the bidirectional switched power supply 20 of the present invention can control the charging of the first battery BATA and the second battery BATB by the output terminal SYS only by using a single power stage 21. In detail, the power path management circuit 23 includes a first power path switch S4A and a second power path switch S4B. The first power path switch S4A and the second power path switch S4B are, for example but not limited to, NMOS transistors or PMOS transistors. The first power path switch S4A is electrically connected between a first output node SYSA and the first battery BATA. The second power path switch S4B is electrically connected between a second output node SYSB and the second battery BATB. The first output node SYSA and the second output node SYSB are nodes having the same voltage as the output terminal SYS. Therefore, the first power path switch S4A and the second power path switch S4B are actually electrically connected to the output terminal SYS. . That is to say, compared with the prior art bidirectional switched power supply 10, two different output nodes are required to electrically connect two batteries of different battery capacities (ie, the first output terminal OUTA and the first shown in FIG. 1) The two output terminals OUTB are electrically connected to the first battery BATA and the second battery BATB respectively. The bidirectional switched power supply 20 of the present invention can be electrically connected to the first battery BATA via the power path management circuit 23 only by using a single output terminal SYS. And a second battery BATB. It should be noted that the number of batteries electrically connected to the two-way switching power supply 20 of the present invention is not limited to two, and may be two or more. The two batteries described in the embodiment (the first battery BATA and the first The second battery BATB) is only for convenience of illustration, and should not be limited by the number of batteries when implemented.

The battery capacity (Battery Capacity) of the first battery BATA and the second battery BATB described in this embodiment may not be the same as each other. Among them, the battery can be charged by a charge The state (SOC) (in %) or a voltage level (in V) is indicated, and the method of measuring the battery power is known to those skilled in the art, and thus will not be described herein. For example, in the present embodiment, the battery power of the first battery BATA is represented by the first battery voltage VBATA such as, but not limited to, 4.35V, and the battery power of the second battery BATB is the second battery voltage VBATB, for example. However, it is not limited to being expressed as 4.2V.

When the bidirectional switching power supply 20 is operable in the charging mode, the bidirectional switching power supply 20 bucks the supply voltage VBUS provided by the supply terminal BUS to the output terminal SYS via the power stage 21, that is, The higher supply voltage VBUS is converted to a lower output voltage VSYS. Since the output terminal SYS is electrically connected to the first battery BATA and the second battery BATB via the first power path switch S4A and the second power path switch S4B, the present invention may further include a power path controller 24, according to which The first switch signal SLA and the second switch signal SLB are generated by the power path controller 24 to control the turn-on and turn-off of the first power path switch S4A and the second power path switch S4B, respectively, and then control the pair respectively. Charging of the first electric BATA and the second battery BATB. The first power path switch S4A and the second power path switch S4B may be a transistor. The parasitic diode of the transistor can block the current flowing from the output terminal SYS to the first battery BATA and the second battery BATB, so the charging of the first battery BATA and the second battery BATB can be performed by the first power path switch S4A and the Two power path switches S4B are used for control.

When the power provided by the power source connected to the supply terminal BUS is insufficient, the bidirectional switched power supply 20 can supply power to the supply terminal BUS from the output terminal SYS electrically connected to the first battery BATA or the second battery BATB, which is the power supply mode. . In the power mode, the same circuit shown in Figure 2 will become a boost-type switching power supply, the first battery BATA or the second The battery BATB boosts the lower first battery voltage VBATA or the second battery voltage VBATB to a higher supply voltage VBUS via the power stage 21, respectively, and supplies power to the supply terminal BUS.

Please continue to refer to Figure 2. In some applications of this creation, a power protection can be selectively (optionally) between the supply BUS and the upper bridge switch S2 (ie between the supply BUS and a power protection node MID). The crystal S1, which protects the transistor S1, has a function of preventing current from flowing backward. As shown in FIG. 2, the parasitic diode anode of the power protection transistor S1 is electrically connected to the supply terminal BUS, and the cathode thereof is electrically connected to the upper bridge switch S2, that is, the polarity of the parasitic diode of the power protection transistor S1 and the upper side. The polarity of the parasitic diode of the bridge switch S2 is opposite, so when the voltage of the end of the upper bridge switch S2 (MID or LX) is higher than the supply voltage VBUS, the parasitic diode of the power protection transistor S1 can be blocked from the upper bridge switch. S2 flows back to the supply side BUS. In this way, power protection or control functions can be provided.

In an embodiment, the operating circuit 22, the power protection transistor S1, the power path management circuit 23, and the power path controller 24 may be integrated into a control circuit 30 in whole or in part by integrated circuit fabrication techniques.

Please refer to Figures 3A-3E, which show several other embodiments of the first power path switch and the second power path switch. The output SYS of this creation can be electrically connected to the two batteries BATA and BATB. The first battery BATA and the second battery BATB are, for example but not limited to, batteries that may be internal or external to an electronic device or a mobile power source. Referring to an embodiment as shown in FIG. 3A, the first power path switch S4C and the second power path switch S4D may be a transistor with a variable parasitic diode polarity. The adjustable polarity transistor has a parasitic diode with adjustable polarity direction, and when the first battery BATA or the second battery BATB is charged at the output terminal SYS, the anode of the parasitic diode can be yin The pole direction is opposite to the charging direction. Referring to an embodiment shown in FIG. 3B, the output terminal SYS and the first power path switch S4A can be electrically connected via the first resistor RA, and the output terminal SYS and the second power path switch S4B can pass through the first The two resistors RB are electrically connected. Referring to an embodiment as shown in FIG. 3C, the first power path switch S4A and the first battery BATA can be electrically connected via the first resistor RA, and the second power path switch S4B and the second battery BATB can be connected via The second resistor RA is electrically connected. Please refer to an embodiment as shown in FIG. 3D. The resistance connection shown in FIG. 3D is the same as that in FIG. 3B. The difference between the two is that in FIG. 3B, the first power path switch S4A and the second power path switch S4B are a transistor; and in the 3D The first power path switch S4C and the second power path switch S4D are a transistor with a variable parasitic diode polarity. Please refer to an embodiment as shown in FIG. 3E. The resistance connection shown in FIG. 3E is the same as that in FIG. 3C. The difference between the two is that in the 3C, the first power path switch S4A and the second power path switch S4B are a transistor; and in FIG. 3E The first power path switch S4C and the second power path switch S4D are a transistor with a variable parasitic diode polarity. It should be noted that, in the 3B-3E diagram, the purpose of setting the first resistor RA and the second resistor RB is to detect a current, wherein the voltage across the first resistor RA and the second resistor RB can respectively represent a pair Information on the charging current of the first battery BATA and the second battery BATB. However, the method of current detection is not limited to this, and other methods of detecting current can still be used in the scope of the present invention.

Please refer to Figures 4A-4C for a number of embodiments showing how the creation generates operational signals. On the one hand, the operation circuit 22 is used to cause the operation circuit 22 to generate the operation signal SL1 according to the output voltage VSYS or its related signal information, thereby controlling the power conversion from the supply terminal BUS to the output terminal SYS; The first power signal path is opened by the first switching signal SLA and the second switching signal SLB generated by the power path controller 24 The S4A and the second power path switch S4B are turned off, and the charging of the first electric BATA and the second battery BATB is controlled separately. According to the relationship between the output voltage or its associated signal, the first battery voltage or its associated signal, and the second battery voltage or its associated signal, the operating circuit 22 and the power path controller 24 of the present invention are based on, for example, 4A-4C. One of the modes shown in the figure or a combination thereof, which respectively generates the operation signal SL1 and the first switching signal SLA and the second switching signal SLB, will be described in detail below. It should be noted that, in an embodiment, the operating circuit 22 and the power path controller 24 of the present invention may be based on the output voltage or its associated signal, the first battery voltage or its associated signal, and the second battery voltage or its associated signal. The relationship between the two generates the operation signal SL1 and the first switching signal SLA and the second switching signal SLB, respectively. In other embodiments, the operation circuit 22 and the power path controller 24 of the present invention can further add the output voltage or the related signal, the first battery voltage or the information according to the charging current of the first battery BATA and the second battery BATB. The relationship between the associated signal and the second battery voltage or its associated signal generates the operation signal SL1 and the first switching signal SLA and the second switching signal SLB, respectively.

First, please refer to Figure 4A. In this embodiment, the output voltage VSYS may be determined by adding a safety difference Vos between the first battery voltage VBATA of the first battery BATA and the second battery voltage VBATB of the second battery BATB. As shown, the operational circuit 22 of the present invention can include a comparator 224, a multiplexer 221, an adder 222, an error amplifier 223, a PWM (pulse width modulation) comparator 228, and a drive circuit 229. . The comparator 224 may first compare the level of the first battery voltage VBATA or its associated signal with the second battery voltage VBATB or its associated signal to produce a comparison result. Then, the multiplexer 221 can determine, according to the comparison result, that the level between the first battery voltage VBATA or its related signal or the second battery voltage VBATB or its related signal is selected to be larger. That is, if the comparator 224 loses The comparison result is that the first battery voltage VBATA or its associated signal is greater than the second battery voltage VBATB or its associated signal, and the output of the multiplexer 221 is the first battery voltage VBATA or its associated signal. If the comparison result output by the comparator 224 is that the first battery voltage VBATA or its associated signal is less than the second battery voltage VBATB or its associated signal, the output of the multiplexer 221 is the second battery voltage VBATB or its associated signal. Next, the adder receives the output of the multiplexer 221 and sums the output of the multiplexer 221 with the safety difference Vos or its associated signal to produce an aggregated result. Next, the error amplifier 223 compares the summed result with a reference voltage Vref1 to generate a comparison output signal, which is an error amplification signal VEA in the present embodiment (but the error amplifier 223 can also be changed to a comparator, and the comparison output signal is digital. Signal, after the explanation). The PWM signal generator 228 compares the error amplification signal VEA with a sawtooth signal to generate a PWM signal. The driving circuit 229 generates an operation signal SL1 according to the PWM signal, thereby controlling power conversion from the supply terminal BUS to the output terminal SYS. It can be seen that the magnitude relationship between the first battery voltage VBATA or its associated signal and the second battery voltage VBATB or its associated signal affects the generation of the error amplification signal VEA, thereby affecting the generation of the operation signal SL1. By the feedback control of the circuit, the output voltage VSYS can be adjusted to the first battery voltage VBATA and the second battery voltage VBATB level plus a safety difference Vos, that is, VSYS=max (VBATA, VBATB) +Vos. In addition, in this case, since there is at least one safety difference Vos between the output voltage VSYS and any of the battery voltages, the control of the first power path switch S4A and the second power path switch S4B can be determined according to the charging requirement of the battery. There is no need to worry about and prevent the battery from charging each other.

It should be noted that the operation circuit 22 can generate the operation signal SL1 in various manners. The above description is only an example, and the operation circuit 22 can also use other methods to generate the operation signal SL1 of the fixed frequency or the frequency conversion. For example, the error amplifier 223 can be changed to Comparator (error amplification signal VEA) Change to digital signal), and generate a pulse with a fixed pulse width as the operation signal SL1 according to the rising or falling edge of its output, and so on. Moreover, if the signal output by the PWM signal generator 228 is sufficient to push the power stage 21, the drive circuit 229 can be omitted. All such changes should be included in the scope of this creation.

Please refer to Figure 4B. In this embodiment, the output voltage VSYS can be determined by a larger level between the first battery voltage VBATA and the second battery voltage VBATB. As shown in the figure, the operation circuit 22 of the present invention may include a comparator 224, a multiplexer 221, and an error amplifier 223 (to simplify the drawing and indicate that the operation signal SL1 is not limited to the 4A diagram, therefore the PWM is omitted. Comparator 228 and drive circuit 229). The comparator 224 may first compare the level of the first battery voltage VBATA or its associated signal with the second battery voltage VBATB or its associated signal to produce a comparison result. Then, the multiplexer 221 can determine, according to the comparison result, that the level between the first battery voltage VBATA or its related signal or the second battery voltage VBATB or its related signal is selected to be larger. In detail, if the level of the first battery voltage VBATA or its associated signal is greater than the level of the second battery voltage VBATB or its associated signal, the output of the multiplexer 221 is the first battery voltage VBATA or its associated signal. Next, the error amplifier compares the output of the multiplexer 221 with the reference voltage Vref1 to generate an error amplification signal VEA. The operation circuit 22 can generate the operation signal SL1 according to the error amplification signal VEA, and control the power conversion from the supply terminal BUS to the output terminal SYS, for example, but not limited to, the method shown in FIG. 4A; . By the feedback control of the circuit, the output voltage VSYS can be adjusted to the first level of the first battery voltage VBATA and the second battery voltage VBATB, that is, VSYS=max (VBATA, VBATB).

On the other hand, due to the output voltage VSYS and the higher level battery voltage There is no safety difference, so it is preferable to control the charging current of the battery, that is, to control the first power path switch S4A and the second power path switch S4B. (Of course, if there is a safety difference, it can be controlled as well.) In this embodiment, the comparator 224 can output the comparison result to the power path controller 24 to generate the first switching signal SLA and the first according to the comparison result. The second switching signal SLB controls the first power path switch S4A and the second power path switch S4B. Assuming that the first battery voltage VBATA level is greater than the second battery voltage VBATB, the generated first switching signal SLA can, for example, cause the first power path switch S4A to be fully turned on, and the generated second switching signal SLB can, for example, be second. The power path switch S4B operates in a linear mode. If the second battery voltage VBATB level is greater than the first battery voltage VBATA, the second power path switch S4B can be turned on completely, and the first power path switch S4A can be operated in the linear mode.

Please refer to Figure 4C. The control mode of this embodiment preferentially considers the charging current demand of the battery, and controls the first power path switch S4A and the second power path switch S4B according to the charging current demand, but when the output voltage VSYS and the first battery voltage VBATA or the second When the difference of one of the battery voltages VBATB is less than a predetermined voltage level, the corresponding first power path switch S4A or the second power path switch S4B is turned off. As shown in the figure, the operation circuit 22 of the present invention may include a first comparator 224, a multiplexer 221, an error amplifier 225, and a second comparator 226 (to simplify the drawing and indicate that the operation signal SL1 is not limited to In the manner of Fig. 4A, the error amplifier 223, the PWM comparator 228, and the drive circuit 229) are omitted. The first comparator 224 can first compare the level of the first battery voltage VBATA or its associated signal with the second battery voltage VBATB or its associated signal to generate a comparison result. Then, the multiplexer 221 can determine, according to the comparison result, that the level between the first battery voltage VBATA or its related signal or the second battery voltage VBATB or its related signal is selected to be larger. Next, the error amplifier 225 will be multiplexed The output of the 221 is compared with the output voltage VSYS or its associated signal to produce an error amplification signal. Next, the second comparator 226 compares the error amplification signal with a preset voltage level, and the comparison result indicates whether the difference between the output voltage VSYS and the higher of the first battery voltage VBATA or the second battery voltage VBATB is less than a pre-predetermined value. Set the voltage level. If it is less than the preset voltage level, the power path controller 24 turns off the corresponding first power path switch S4A or the second power path switch S4B, but the other battery can continue to receive the charging. The purpose of the above design is to prevent the batteries from being charged to each other, but if the phenomenon of mutual charging of the batteries can be tolerated, no special treatment is required.

It should be noted that FIG. 4C is only one of the embodiments, and the circuit can have multiple equivalent ways to achieve the same purpose. For example, the preset voltage level can be added to the output of the multiplexer 221, and the error amplifier 225 can be changed to a comparator. Then the second comparator 226 can be omitted, and the error amplifier 225 (now changed to a comparator). The output is provided to the power path controller 24. Furthermore, the output voltage VSYS can also be compared to the first battery voltage VBATA and the second battery voltage VBATB, rather than only the higher of the first battery voltage VBATA or the second battery voltage VBATB, and so on.

The control methods of the above 4A-4C diagrams may be selected one by one, or may be combined without conflict, and all components in the 4A-4C diagram may be included in the hardware circuit for convenience. The user selects the control method.

Please refer to Figures 5A-5B, which show several embodiments of the power stage that were created in the power mode. When the bidirectional switched power supply 20 is in the power mode, the power stage 21 is a boost type switching power stage circuit. In an embodiment, the upper bridge switch S2 in FIG. 2 can be replaced with a Schottky diode SD1, but the power protection transistor S1 remains, as shown in FIG. 5A. Alternatively, both the upper bridge switch S2 and the power protection transistor S1 in Fig. 2 can be used. A Schottky diode SD1 is replaced, as shown in Figure 5B.

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 protection transistor S1, the upper bridge switch S2, the lower bridge switch S3, and the first power path switch ( S4A, S4C) and the second power path switch (S4B, S4D) may be PMOS or NMOS, and the circuit can be correspondingly transformed. As another example, power path controller 24 can be incorporated in operational circuit 22 without necessarily being a separate 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‧‧‧Power Path Management Circuit

24‧‧‧Power Path Controller

30‧‧‧Control circuit

BATA‧‧‧First battery

BATB‧‧‧second battery

L‧‧‧Inductance

LX‧‧‧ switching node

MID‧‧‧ power protection node

BUS‧‧‧Supply

S1‧‧‧Power Protection Transistor

S2‧‧‧Upper Bridge Switch

S3‧‧‧Bridge switch

S4A‧‧‧First power path switch

S4B‧‧‧Second power path switch

SL1‧‧‧ operation signal

SLA‧‧‧First switch signal

SLB‧‧‧Second switch signal

SYS‧‧‧ output

SYSA‧‧‧ first output node

SYSB‧‧‧ second output node

VBATA‧‧‧First battery voltage

VBATB‧‧‧second battery voltage

VBUS‧‧‧ supply voltage

VSYS‧‧‧ output voltage

Claims (13)

A bidirectional switching power supply for converting a supply voltage provided by a supply terminal into an output voltage to an output terminal in a charging mode, and supplying power to the supply from the output terminal in a power supply mode The two-way switching power supply includes: a single power stage coupled between the supply end and the output end for performing power conversion between the two; and an operation circuit for generating one of the control power levels The power path management circuit is coupled to the output end. The power path management circuit includes: a first power path switch, one end of which is coupled to the output end, and the other end of which is coupled In a first battery, the first battery has a first battery voltage; and a second power path switch, one end of which is coupled to the output end, and the other end of which is coupled to a second battery, the second The battery has a second battery voltage; and a power path controller for controlling the power path management circuit. The bidirectional switched power supply of claim 1, wherein the bidirectional switched power supply is controlled by one of the following methods or a combination thereof: (1) the output voltage is determined by the first battery voltage The second battery voltage is greater between the two and a safety difference is determined; (2) the output voltage is higher than the first battery voltage and the second battery voltage Determining; (3) the power path controller controls to enable the first or second power path switch corresponding to the larger level between the first battery voltage and the second battery voltage to be fully turned on, and the first or The other of the second power path switches operates in a linear mode; or (4) When the difference between the output voltage and the first battery voltage or the second battery voltage is less than a predetermined voltage level, the corresponding first or second power path switch is turned off. The bidirectional switched power supply of claim 2, wherein the operating circuit comprises: a comparator for comparing the first battery voltage or its associated signal with the second battery voltage or its associated signal Leveling to generate a comparison result; a multiplexer, according to the comparison result, determining to select the output of the first battery voltage or its associated signal or the second battery voltage or a related signal between the two An adder receiving the output of the multiplexer and summing the output of the multiplexer with the safety difference or its associated signal to generate a total result; and an error amplifier or comparator The total result is compared with a reference voltage to generate a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal. The bidirectional switched power supply of claim 2, wherein the operating circuit comprises: a comparator for comparing the first battery voltage or its associated signal with the second battery voltage or its associated signal Leveling to generate a comparison result; a multiplexer, according to the comparison result, determining to select the output of the first battery voltage or its associated signal or the second battery voltage or a related signal between the two And an error amplifier or comparator, comparing the output of the multiplexer with a reference voltage to generate a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal. The bidirectional switched power supply of claim 3 or 4, wherein the operating circuit further comprises: determining whether a difference between the output voltage and the first battery voltage or the second battery voltage is less than a preset Voltage level circuit. The bidirectional switching power supply device of claim 1, further comprising a power protection transistor, one end of which is electrically connected to the supply end, and the other end of which is electrically connected to the power level for protecting the supply end Connected to a power supply, the power protection transistor has a parasitic diode whose direction blocks the reverse current flowing from the power stage to the supply terminal. A control circuit for a bidirectional switching power supply for controlling a power stage to convert a supply voltage provided by a supply terminal to an output voltage to an output terminal in a charging mode, and in a power supply mode, The control circuit includes: an operation circuit for generating an operation signal for controlling the power level; a power path management circuit coupled to the output terminal, the power path management The circuit includes: a first power path switch, one end of which is coupled to the output end, the other end of which is coupled to a first battery, the first battery has a first battery voltage; and a second power path switch One end is coupled to the output end, the other end of the second battery is coupled to a second battery, and the second battery has a second battery voltage, wherein the first power path switch and the second power path switch The first battery and the second battery are coupled to the same output end; and a power path controller for controlling the power path management circuit. The control circuit of the bidirectional switched power supply as described in claim 7, wherein the control circuit controls the bidirectional switched power supply according to one of the following modes or a combination thereof: (1) the output voltage is determined by the first A higher level between a battery voltage and the second battery voltage is determined by summing a safety difference; (2) the output voltage is determined by a greater level between the first battery voltage and the second battery voltage; (3) the power path controller controls the first battery voltage and the second battery The first or second power path switch corresponding to the higher level between the voltages is fully turned on, and the other of the first or second power path switches is operated in the linear mode; or (4) when the output voltage When the difference between the first battery voltage or the second battery voltage is less than a predetermined voltage level, the corresponding first or second power path switch is turned off. The control circuit of the bidirectional switched power supply device of claim 8, wherein the operating circuit comprises: a comparator for comparing the first battery voltage or its associated signal with the second battery voltage or its associated signal Level between the two to generate a comparison result; a multiplexer, according to the comparison result, determines to select a level between the first battery voltage or its associated signal or the second battery voltage or its associated signal a larger one; an adder receiving the output of the multiplexer and summing the output of the multiplexer with the safety difference or its associated signal to generate a total result; and an error amplifier or comparator, Comparing the summation result with a reference voltage to generate a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal. The control circuit of the bidirectional switched power supply device of claim 8, wherein the operating circuit comprises: a comparator for comparing the first battery voltage or its associated signal with the second battery voltage or its associated signal Level between the two to generate a comparison result; a multiplexer, according to the comparison result, determines to select a level between the first battery voltage or its associated signal or the second battery voltage or its associated signal a larger one; and an error amplifier or comparator that compares the output of the multiplexer with a reference voltage Generating a comparison output signal; wherein the operation circuit generates the operation signal according to the comparison output signal. The control circuit of the bidirectional switched power supply according to claim 9 or 10, wherein the operating circuit further comprises: determining whether a difference between the output voltage and the first battery voltage or the second battery voltage is less than A circuit with a preset voltage level. The control circuit of the bidirectional switched power supply device of claim 7, wherein the first or second power path switch comprises a transistor having a parasitic diode, the direction of which is blocked The output flows current to the first or second battery. The control circuit of the bidirectional switched power supply according to claim 7, wherein the first or second power path switch comprises a transistor with a variable parasitic diode polarity, the adjustable parasitic diode The polar transistor has a parasitic diode that is adjustable in polarity.