Control circuit, interleave power supply, and main switch control circuit

Abstract

To provide a control circuit capable of realizing an interleave power supply with an input monitoring function without increasing the number of terminals of a main switch control circuit.SOLUTION: Control circuits 100a and 100b have an interleave signal input unit 110, an interleave control unit 120, a driving unit 130, an interleave output signal generation unit 150, and a mode determination unit 140, and can perform either mode by switching between an interleave transmission mode performing an interleave operation and an input voltage monitoring mode monitoring input voltage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control circuit, an interleaved power supply, and a main switch control circuit. [Background technology]

[0002] Conventionally, an interleaved power supply that controls a PFC circuit with a multi-stage converter is known (see, for example, Patent Document 1). As such an interleaved power supply, the following interleaved power supply (interleaved power supply 900 according to the background art) is conceivable. That is, as shown in Fig. 7, the interleaved power supply 900 according to the background art includes a rectifier circuit 910, a main converter 920 having a main switch 922 that performs switching operation, and secondary converters 930 and 940 having secondary switches 932 and 942 that perform switching with a predetermined phase difference with respect to the switching operation of the main switch 922.

[0003] The main converter 920 has a main switch control circuit 800 (leader IC) that controls the main converter 920, and the main switch control circuit 800 outputs an interleave signal to the downstream converter (sub converter 930) via an interleave output terminal IL_OUT (hereinafter, IL_OUT terminal).

[0004] The slave converters 930, 940 have control circuits 700a, 700b (follower ICs) that control the slave converters 930, 940, and the control circuits 700a, 700b have an interleave input terminal IL_IN (hereinafter referred to as the IL_IN terminal) to which an interleave signal is input from the previous converter, and an IL_OUT terminal that outputs an interleave signal to the subsequent converter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5409935 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, in the field of switching power supplies such as interleaved power supplies, there has been a demand for an input voltage monitoring function that monitors the input voltage and stops the PFC circuit when the input voltage falls below a predetermined voltage. However, the main switch control circuit 800 of the interleaved power supply 900 according to the background art already has many terminals, such as an FB terminal that receives feedback from the output voltage and a COMP terminal that adjusts the on-width, and if an input voltage monitoring function is to be added, the number of terminals of the main switch control circuit 800 will increase, which may cause problems such as an increase in size or the need for design changes.

[0007] Therefore, the present invention has been made to solve the above problems, and has an object to provide a control circuit capable of realizing an interleaved power supply having an input monitoring function without increasing the number of terminals of the main switch control circuit. Another object is to provide such an interleaved power supply. Still another object is to provide a main switch control circuit for use in such an interleaved power supply. [Means for solving the problem]

[0008] The control circuit of the present invention comprises a main converter having a main switch that performs switching operation, and a slave converter having a slave switch that switches with a predetermined phase difference relative to the switching operation of the main switch, and controls the switching operation of the slave switch for an interleaved power supply that forms a master-slave relationship between the main converter and the slave converter.The control circuit comprises an interleave signal input unit, an interleave control unit, a drive unit, an interleave output signal generation unit, and a mode determination unit, and is capable of switching between an interleave transmission mode that performs interleave operation and an input voltage monitoring mode that monitors the input voltage.

[0009] The interleaved power supply of the present invention comprises a main converter having a main switch that performs switching operation, and a slave converter having a slave switch that switches with a predetermined phase difference relative to the switching operation of the main switch, forming a master-slave relationship between the main converter and the slave converter, the main converter having a main switch control circuit that controls the switching operation of the main switch, and the slave converter having the control circuit of the present invention as a control circuit that controls the switching operation of the slave switch.

[0010] The main switch control circuit of the present invention comprises a main converter having a main switch that performs switching operation, and a slave converter having a slave switch that switches with a predetermined phase difference relative to the switching operation of the main switch, and in the main switch control circuit that controls the switching operation of the main switch for an interleaved power supply that forms a master-slave relationship between the main converter and the slave converter, the main switch control circuit has a feedback terminal that inputs a voltage based on an output voltage, and a voltage monitoring unit that monitors the voltage based on the output voltage input to the feedback terminal, and when a main converter stop signal is output from the control circuit that controls the switching operation of the slave switch, the main converter stop signal is input to the feedback terminal, and the voltage monitoring unit determines whether or not to stop the main converter based on the main converter stop signal input to the feedback terminal. Effect of the Invention

[0011] According to the control circuit and interleaved power supply of the present invention, the control circuit can switch between an interleaved transmission mode in which an interleaved operation is performed and an input voltage monitoring mode in which the input voltage is monitored, so that the input voltage can be monitored by the slave converter rather than the main converter. Therefore, it is not necessary to provide new terminals to the main switch control circuit, which already has many terminals. Therefore, it is possible to provide an interleaved power supply that can monitor the input voltage without increasing the number of terminals of the main switch control circuit.

[0012] Furthermore, according to the main switch control circuit of the present invention, when a main converter stop signal is output from the control circuit that controls the switching operation of the slave switch, the main converter stop signal is input to the feedback terminal, and the voltage monitoring unit determines whether or not to stop the main converter based on the main converter stop signal input to the feedback terminal, so that it is possible to input the main converter stop signal from the control circuit to the already provided feedback terminal and determine whether or not to stop the main converter. As a result, there is no need to provide a new terminal for inputting the main converter stop signal. [Brief description of the drawings]

[0013] [Figure 1] 1 is a circuit diagram showing an interleaved power supply 1 according to an embodiment. [Diagram 2] FIG. 2 is a block diagram shown for explaining a control circuit 100 (100a, 100b) according to the first embodiment. [Diagram 3] FIG. 1 is a block diagram for explaining a main switch control circuit 200 according to a first embodiment. [Figure 4] FIG. 2 is a diagram for explaining the relationship between the main switch control circuit 200 and a control circuit 100b (last stage of the follower). [Diagram 5] 5 is a timing chart of the main switch control circuit 200, the control circuit 100a (follower middle stage), and the control circuit 100b (follower final stage). In FIG. 5, COMP, FB, IL_OUT, OUT, IL_IN, and VIS indicate the voltages of the respective terminals, IL_OUT internal MOS indicates the voltage applied to the changeover switch 170, and IL_OUTcharge indicates the charging voltage for the changeover switch 170. [Figure 6] FIG. 11 is a circuit diagram showing an interleaved power supply 2 according to a second embodiment. [Figure 7] FIG. 9 is a circuit diagram showing an interleaved power supply 900 according to the background art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The control circuit, interleaved power supply, and main switch control circuit of the present invention will be described below based on the embodiments shown in the drawings. Note that the embodiments described below do not limit the invention according to the claims. Also, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention.

[0015] [Embodiment 1] 1. Configuration of the interleaved power supply 1 according to the first embodiment The interleaved power supply 1 according to the first embodiment is an interleaved power supply in which a plurality of converters are connected in multiple stages. As shown in Fig. 1, the interleaved power supply 1 includes a rectifier circuit 10, a main converter 20 having a main switch 22 that performs switching operation, and sub converters 30 and 40 having sub switches 32 and 42 that perform switching with a predetermined phase difference with respect to the switching operation of the main switch 22, and the main converter 20 and the sub converters 30 and 40 are connected in parallel between the rectifier circuit 10 and an output capacitor C3. In the interleaved power supply 1, a main-sub converter 20 and the sub converters 30 and 40 form a main-sub converter relationship. Both the main converter 20 and the sub converters 30 and 40 perform current criticality operation.

[0016] The rectifier circuit 10 includes a bridge diode BD that, for example, full-wave rectifies the AC current of a commercial power source to a pulsating current, and a smoothing capacitor C2. Two input power lines that are input to the bridge diode BD are connected to the VIS terminal of the control circuit 100b of the secondary converter 40 via a diode and a resistor R16.

[0017] (1) Main Converter 20 and Main Switch Control Circuit 200 The main converter 20 includes an inductor 21, a main switch 22, a diode D1, and a main switch control circuit 200 (leader IC). The inductor 21, the main switch 22, and the diode D1 form a boost chopper circuit.

[0018] In the first embodiment, the main switch 22 is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), but may be an IGBT or any other suitable switch element. The inductor 21 and the diode D1 may also be suitable inductors and diodes.

[0019] The main switch control circuit 200 has eight terminals: a Vcc terminal, an OUT terminal, a GND terminal, a VDZC terminal, an OCL terminal, an IL_OUT terminal, a COMP terminal, and an FB terminal (feedback terminal).

[0020] The Vcc terminal is connected to an external power supply Vcc and receives a voltage from the external power supply Vcc. The OUT terminal is connected to the gate electrode of the main switch 22 and outputs to the gate electrode a signal that controls the on / off of the main switch 22. The GND terminal is connected to a reference potential.

[0021] The VDZC terminal is connected to the midpoint of resistors R1 and R2 connected in series with the drain electrode of the main switch 22, and receives the voltage obtained by dividing the drain voltage of the main switch 22 by the resistors R1 and R2.

[0022] The OCL terminal is connected to a resistor R4 and a capacitor C7, and is connected between the source electrode of the main switch 22 and the midpoint of the resistor R3 via the resistor R4. The OCL terminal monitors whether an overcurrent flows through the main switch 22 by monitoring a voltage determined by the resistor R3.

[0023] The IL_OUT terminal is connected to the IL_IN terminal of the control circuit 100a (follower IC), and outputs an interleaved signal to the control circuit 100a.

[0024] The COMP terminal is an output terminal of a feedback error amplifier connected to the capacitor C6. The main switch control circuit 200 uses the voltage of the COMP terminal to determine the ON width of the main switch 22 and control the output voltage.

[0025] The FB terminal is connected to the capacitor C5, resistors R5 and R6, and the IL_OUT terminal of the control circuit 100b. A voltage obtained by dividing the output voltage by resistors R5 and R6 is input to the FB terminal. When the control circuit 100b goes into the input voltage monitoring mode and outputs a main switch stop signal, the input voltage is input to the FB terminal.

[0026] Next, the internal configuration of the main switch control circuit 200 will be described. As shown in FIG. 3, the main switch control circuit 200 includes a critical point detection unit 210, a voltage monitoring unit 220, a logic unit 240, a driving unit 250, and an interleaved signal output unit 260.

[0027] The critical point detection unit 210 detects the timing at which the current flowing through the inductor 21 becomes zero based on the voltage obtained by dividing the drain voltage of the main switch 22 input from the VDZC terminal by resistors R1 and R2, and outputs a critical point detection signal to the logic unit 240.

[0028] The voltage monitoring unit 220 outputs on-width information to the logic unit 240 based on the voltage of the COMP terminal, which is the error amplifier output voltage generated by the voltage input to the FB terminal, and outputs a standby signal to the logic unit 240 when a main converter stop signal is received from the control circuit 100b via the FB terminal.

[0029] The voltage monitoring unit 220 is connected to the FB terminal and the COMP terminal. The voltage monitoring unit 220 includes an output overvoltage detection unit (FB_OVP) 224, a low input voltage detection unit (FB_open) 223, an input voltage stop unit (FB_stby) 222, an on-width adjustment unit (FB_ref) 221, and COMP monitoring units (COMP(pre) 231 and COMP(bst) 232).

[0030] An output overvoltage detection unit (FB_OVP) 224 detects whether the output voltage of the interleaved power supply 1 is an overvoltage by comparing whether the FB voltage of the FB terminal is greater than a predetermined value.

[0031] The low input voltage detection unit (FB_open) 223 detects whether the input voltage of the interleaved power supply 1 is excessively low by comparing whether the FB voltage of the FB terminal is smaller than a predetermined value.

[0032] The input voltage stopping unit (FB_stby) 222 determines whether or not the FB voltage at the FB terminal exceeds a predetermined value, thereby determining whether or not to stop the operation of the main converter 20 and the secondary converters 30, 40. The predetermined value of the FB terminal of the input voltage stopping unit 222 is set to a value higher than the predetermined value of the FB terminal of the output overvoltage detection unit 224.

[0033] The on-width adjustment unit (FB_ref) 221 charges and discharges, within a predetermined range, a capacitor C6 connected to a COMP terminal which is an error amplifier output voltage.

[0034] The COMP monitoring unit COMP(pre) 231 detects whether the COMP voltage falls below a predetermined voltage COMP(pre). The COMP monitoring unit COMP(pre) 232 detects whether the COMP voltage exceeds a predetermined voltage COMP(bst).

[0035] When the output of any one of the output overvoltage detection unit (FB_OVP) 224, the low input voltage detection unit (FB_open) 223, and the input voltage stop unit (FB_stby) 222 becomes Hi, the OR operator 227 outputs Hi to the logic unit 240. When any one of the low input voltage detection unit (FB_open) 223 and the input voltage stop unit (FB_stby) 222 is Hi, the OR operator 226 inputs to the standby mode signal generation unit 235 and outputs a standby signal to the logic unit 240.

[0036] The logic unit 240 outputs a control signal to the driver 250 based on the critical point detection signal from the critical point detector 210 and the on-width signal and standby signal from the voltage monitor 220, and outputs control signal output information to the interleave signal output unit 260.

[0037] The drive unit 250 outputs a signal for turning on and off the main switch 22 based on the control signal to the main switch 22 via an OUT terminal.

[0038] The interleaved signal output unit 260 generates an interleaved output signal based on the interleaved output information, and outputs the interleaved signal to the control circuit 100a via the IL_OUT terminal.

[0039] (2) Slave Converter 30 and Control Circuit 100a 1, the slave converter 30 includes an inductor 31, a slave switch 32, a diode D2, and a control circuit 100a as a control circuit of the present invention, and the inductor 31, the slave switch 32, and the diode D2 form a boost chopper circuit. The slave converter 30 has a similar configuration to the main converter 20, except that a capacitor C4 is provided instead of the resistor R1, a control circuit 100 (follower IC) is provided instead of the main switch control circuit 200, and the control circuit 100a has a VIS terminal and an IL_IN terminal instead of the FB terminal and the COMP terminal.

[0040] The control circuit 100a has a Vcc terminal, an OUT terminal, a GND terminal, a VDZC terminal, an OCL terminal, a VIS terminal, an IL_OUT terminal, and an IL_IN terminal. The connections and configurations of the Vcc terminal, the OUT terminal, the GND terminal, the VDZC terminal, the OCL terminal, and the IL_OUT terminal are similar to those of the main switch control circuit 200, and therefore will not be described.

[0041] The IL_IN terminal is a terminal for inputting an interleave signal from the main switch control circuit 200. The IL_IN terminal is connected to the IL_OUT terminal of the main switch control circuit 200 via a resistor R11.

[0042] The VIS terminal is connected to a resistor R10 and a capacitor C11. In the control circuit 100a, the VIS terminal is connected to an external power supply Vcc, and the voltage of the VIS terminal is higher than the threshold voltage VIS(INTER).

[0043] The control circuit 100a is a control circuit that controls the switching operation of the slave switch 32. As shown in Fig. 2, the control circuit 100a includes an interleave signal input unit 110, an interleave control unit 120, a drive unit 130, a mode determination unit 140, an interleave output signal generation unit 150, a main converter control signal generation unit 160, and a changeover switch 170.

[0044] The control circuit 100a is a control circuit capable of switching between an interleave transfer mode in which an interleave operation is performed and an input voltage monitoring mode in which an input voltage is monitored. The control circuit 100a is a control circuit other than the final stage, and therefore operates in the interleave transfer mode. Although two control circuits are used in the first embodiment, three or more control circuits may be used. In this case, the control circuits other than the final stage operate in the interleave transfer mode, and the control circuit of the final stage operates in the input voltage monitoring mode.

[0045] The interleave signal input unit 110 acquires an interleave input signal input from the previous converter (main switch control circuit 200) via the IL_IN terminal, and outputs ON width information generated based on the interleave input signal to the interleave control unit 120.

[0046] The interleave control unit 120 outputs to the drive unit 130 a control signal for turning on and off the slave switch 32 at a timing adjusted based on the on-width information output from the interleave signal input unit 110. When an interleave signal transmission signal is input from the mode determination unit 140, the interleave control unit 120 outputs interleave output information generated based on the on-width information to the interleave output signal generation unit 150.

[0047] The driver 130 turns on and off the slave switch 32 based on a control signal from the interleave controller 120. The driver 130 outputs a switching pulse for turning on and off the slave switch 32 to the gate electrode of the slave switch 32 via a terminal OUT.

[0048] The mode determination unit 140 acquires input voltage information via the VIS terminal, and determines whether the mode is the interleave transmission mode or the input voltage monitoring mode based on the input voltage information. Specifically, when the voltage (VIS voltage) input from the VIS terminal exceeds a predetermined threshold VIS(INTER), the mode is determined to be the interleave transmission mode, and when the VIS voltage is equal to or lower than the predetermined threshold VIS(INTER), the mode is determined to be the input voltage monitoring mode (see FIG. 5). In the control circuit 100a, the VIS voltage is always higher than VIS(INTER), so the control circuit 100a always operates in the interleave transmission mode.

[0049] When the mode determination unit 140 determines that the mode is the interleave transfer mode, it outputs an interleave signal transfer signal to the interleave control unit 120, and when it determines that the mode is the input voltage monitoring mode, it outputs an input voltage monitoring mode detection signal to the main converter control signal generation unit 160. Since the control circuit 100a operates in the interleave transfer mode, it outputs an interleave signal transfer signal to the interleave control unit 120.

[0050] The interleave output signal generating unit 150 generates an interleave output signal based on the interleave output information from the interleave control unit 120, and outputs the interleave signal to the IL_IN terminal of the control circuit 100b via the changeover switch 170 and the IL_OUT terminal.

[0051] Explaining the interleaved output signal generation unit 150 in more detail, as shown in FIG. 4, the interleaved output signal generation unit 150 generates an interleaved output signal using switch elements IL (source1) and IL (sink), and outputs the interleaved output signal to the IL_IN terminal of the next stage (control circuit 100b).

[0052] The main converter control signal generating unit 160 determines whether to maintain or stop the operation of the main converter 20 based on the input voltage monitoring mode detection signal output from the mode determining unit 140. In the control circuit 100a, since it operates in the interleaved transfer mode, the main converter control signal generating unit 160 does not operate.

[0053] (3) Regarding the slave converter 40 and the control circuit 100b 1, the slave converter 40 includes an inductor 41, a slave switch 42, a diode D3, and a control circuit 100b, and the inductor 41, the slave switch 42, and the diode D3 form a boost chopper circuit. The slave converter 40 has the same configuration as the slave converter 30 in the control circuit 100b, except for the connection of the VIS terminal and the IL_OUT terminal.

[0054] In the secondary converter 40, the VIS terminal is connected to the input power supply line of the rectifier circuit 10, and a voltage obtained by dividing the input voltage by resistors R16 and R14 is input thereto.

[0055] The IL_OUT terminal is connected to the FB terminal of the main switch control circuit 200 .

[0056] The IL_IN terminal is a terminal for inputting an interleave signal from the control circuit 100a, and is connected to the IL_OUT terminal of the control circuit 100a via a resistor R15.

[0057] The control circuit 100b is a control circuit that controls the switching operation of the slave switch 42. The control circuit 100b has the same configuration as the control circuit 100a, and includes an interleave signal input unit 110, an interleave control unit 120, a drive unit 130, a mode determination unit 140, an interleave output signal generation unit 150, a main converter control signal generation unit 160, and a changeover switch 170, as shown in FIG.

[0058] The control circuit 100b is a control circuit that can switch between an interleave transmission mode in which an interleave operation is performed and an input voltage monitoring mode in which an input voltage is monitored. The control circuit 100b is a control circuit (follower IC) at the final stage, and therefore operates in the input voltage monitoring mode.

[0059] The interleave signal input unit 110 acquires an interleave input signal input from the previous converter (control circuit 100a) via an IL_IN terminal, and outputs to the interleave control unit 120 on-width information generated based on the interleave input signal.

[0060] The interleave control unit 120 outputs to the drive unit 130 a control signal for turning on and off the slave switch 42 at a timing adjusted based on the on-width information output from the interleave signal input unit 110. In the case of the control circuit 100b, the mode determination unit 140 determines that the control circuit 100b is in the input voltage monitoring mode, and therefore the interleave output information is not output to the interleave output signal generation unit 150.

[0061] The driver 130 turns on and off the slave switch 42 based on a control signal from the interleave controller 120. The driver 130 outputs a switching pulse for turning on and off the slave switch 42 to the gate electrode of the slave switch 42 via a terminal OUT.

[0062] The mode determination unit 140 acquires input voltage information via the VIS terminal, and determines whether the mode is the interleave transmission mode or the input voltage monitoring mode based on the input voltage information. Specifically, when the voltage input from the VIS terminal (VIS voltage) exceeds a predetermined threshold voltage VIS(INTER), the mode is determined to be the interleave transmission mode, and when the VIS voltage is equal to or lower than the predetermined threshold voltage VIS(INTER), the mode is determined to be the input voltage monitoring mode (see FIG. 5). In the control circuit 100b, the VIS voltage is always lower than the threshold voltage VIS(INTER), so the control circuit 100b operates in the input voltage monitoring mode.

[0063] When the mode determination unit 140 determines that the input voltage monitoring mode is selected, it outputs an input voltage monitoring mode detection signal to the main converter control signal generation unit 160 .

[0064] The main converter control signal generator 160 determines whether to maintain or stop the operation of the main converter 20 based on the input voltage monitoring mode detection signal output from the mode determination unit 140. Specifically, when the input voltage monitoring mode detection signal (input voltage information of the VIS terminal) falls below a second threshold voltage VIS(OFF), it outputs a signal to the main switch control circuit 200 to stop the operation of the main converter 20, and when the input voltage monitoring mode detection signal (input voltage information of the VIS terminal) exceeds a predetermined second threshold voltage VIS(ON), it maintains the operation of the main converter 20. Note that the second threshold voltage VIS(ON) is a voltage value smaller than the second threshold voltage VIS(OFF).

[0065] The main converter control signal generating unit 160 and the voltage monitoring unit 220 of the main switch control circuit 200 (leader IC) will be described in detail. When the main converter control signal generating unit 160 determines that the operation of the main converter 20 should be stopped, it generates a main converter stop signal in the switch element IL (source2) in Fig. 4 and charges the capacitor connected to the FB terminal via the IL_OUT terminal.

[0066] In the voltage monitoring unit 220, the voltage at the FB terminal corresponds to the voltage of the input voltage stopping unit 222, and the standby mode signal generating unit 235 generates a standby signal and outputs it to the logic unit 240, thereby stopping the operation of the main switch 22 of the main converter 20. Since the interleave signal is not output, the operation of the control circuits 100a and 100b also stops.

[0067] The changeover switch 170 is connected between the main converter control signal generating unit 160 and the interleave output terminal IL_OUT, and between the interleave output signal generating unit 150 and the interleave output terminal IL_OUT. The changeover switch 170 is turned on when the mode determining unit 140 determines that the mode is the interleave transmission mode and when the main converter control signal generating unit 160 determines that the operation of the main converter 20 is to be stopped, and is turned off when the main converter control signal generating unit 160 determines that the operation of the main converter 20 is to be maintained.

[0068] The main converter control signal generator 160 outputs a main converter stop signal to the FB terminal of the main switch control circuit 200 via the IL_OUT terminal, and also outputs a changeover switch control signal for turning on the changeover switch 170 to the changeover switch 170. Furthermore, when it is determined that the operation of the main converter 20 is to be maintained, it outputs a changeover switch control signal for turning off the changeover switch 170 to the changeover switch 170, and sets the interleave output terminal IL_OUT terminal to an open state.

[0069] 2. Operation of the interleaved power supply 1 according to the first embodiment Next, the operation of the interleaved power supply 1 will be described with reference to the timing chart of FIG.

[0070] (1) Before time t1 (1-1) Main switch control circuit 200 Before time t1, the COMP voltage of the main switch control circuit 200 is constant, and the voltage FB of the FB terminal is at the level of FB_ref, so that the main converter 20 performs normal interleaving operation. That is, the gate output OUT(L) (output voltage of the main switch control circuit) repeats on and off at a predetermined interval. Also, the interleaved output signal IL_OUT repeats on and off in synchronization with the gate output OUT(L).

[0071] (1-2) Control circuit 100a The voltage of the VIS terminal is always higher than VIS(INTER), and the slave converter 30 always operates in the interleaved transfer mode, because the VIS terminal of the slave converter 30 is connected to the external power supply Vcc.

[0072] The interleaved input signal IL_IN is synchronized with the interleaved output signal IL_OUT of the main switch control circuit 200. Then, when the voltage of the interleaved input signal IL_IN turns off, IL(source1) in FIG. 4 turns on, IL_OUTcharge instantaneously becomes positively charged, and the interleaved output signal IL_OUT(F) turns on. That is, when the interleaved input signal IL_IN turns off, the interleaved output signal IL_OUT(F) turns on, and the interleaved output signal IL_OUT(F) is on for the same period as the period during which the interleaved input signal IL_IN is on. When this period ends, the interleaved output signal IL_OUT(F) turns off.

[0073] Therefore, the IL_OUT terminal voltage is repeatedly turned on and off with the phase opposite to that of the IL_IN terminal voltage. Note that the on / off timing chart of the slave switch 32 has the same waveform as the interleaved output signal IL_OUT, so it is omitted from Fig. 5. Also, the IL_OUT internal MOS is always on and connected to the control circuit 100b.

[0074] (1-3) Control circuit 100b In the control circuit 100b, the interleaved output signal IL_OUT(F) of the control circuit 100a is input to the IL_IN terminal. Therefore, the interleaved output signal IL_OUT(F) of the control circuit 100a and the interleaved input signal IL_IN of the control circuit 100b are synchronized. Based on this, the control circuit 100b controls the on / off of the slave switch 42 in synchronization with the interleaved input signal IL_IN and with a phase shift (reversing Hi and Lo).

[0075] In the control circuit 100b, the voltage of the VIS terminal (VIS voltage) is input to the VIS terminal by dividing the input voltage. Since this voltage value is lower than the threshold voltage VIS(INTER), the control circuit 100b operates in the input voltage monitoring mode. Therefore, the IL_OUT voltage is not synchronized with the interleaved input signal IL_IN.

[0076] Since the control circuit 100b is the final stage and there is no next converter, the interleaved output signals IL_OUT, IL_OUTcharge, and the IL_OUT internal MOS are all Lo. When the IL_OUT internal MOS (=changeover switch 170) is off, it is not connected to the FB terminal of the main switch control circuit 200 (leader IC), so the main switch control circuit 200 performs normal PFC operation.

[0077] (2) Time t1~time t2 In the control circuit 100b, the input voltage starts to drop at time t1 in FIG. 5 (see the VIS voltage of the control circuit 100b), and falls below the threshold voltage VIS(OFF) at time t2. Between time t1 and time t2, the voltage of the VIS terminal is sufficiently high, so the IL_OUT internal MOS voltage is Lo, and the changeover switch 170 is in the off (open) state. Therefore, the IL_OUT terminal of the control circuit 100b is not connected to the FB terminal of the main switch control circuit 200, and the main switch control circuit 200 maintains normal PFC operation. During this period, there is no change in the operation of the main switch control circuit 200 and the control circuit 100a.

[0078] When the voltage falls below the threshold voltage VIS(OFF) at time t2, the switch element IL(source2) in Fig. 4 turns on, and IL_OUTcharge is charged by IL(source2). At this time, the IL_OUT internal MOS of the control circuit 100b in Fig. 5 turns on, and is connected to the FB terminal of the main switch control circuit 200, and the FB terminal voltage exceeds FB_STBY. This causes the COMP voltage to start decreasing.

[0079] (3) Time t2~t3 At time t2, the COMP voltage starts to drop, and when it falls below the threshold voltage COMP(pre) at time t3, the interleaved output signal IL_OUT and the gate output OUT are turned off, stopping the operation of the main converter 20. Also, since the interleaved output signal IL_OUT is not output, the control circuits 100a and 100b are also in a state where no interleaved signal is received, and therefore stop operating.

[0080] (4) Time t3~t5 As time passes, when a certain time has passed since the PFC operation stopped, the input voltage starts to rise, and at time t4, when the VIS voltage of the control circuit 100b exceeds the threshold VIS(ON), the IL_OUTcharge and IL_OUT internal MOS are turned off, and the changeover switch 170 is opened. As a result, the interleaved output signal IL_OUT is also turned off and drops to the level of FB_ref. As a result, the COMP voltage starts to rise.

[0081] (5) Time t5~t6 At time t5, when the COMP voltage exceeds COMP(bst), the interleaved output signal IL_OUT and the gate output OUT are turned on to resume the interleaved operation. At this time, while the COMP voltage is low, the on-width of the interleaved output signal IL_OUT and the gate output OUT is short, and the on-width gradually widens. Then, after time t6, the COMP voltage becomes a constant value, and the on-width of the gate output OUT and the interleaved output signal IL_OUT also becomes constant.

[0082] In this way, the interleaved power supply 1 can perform interleaved operation and also realize an input voltage monitoring function.

[0083] 3. Effects of the control circuits 100a and 100b, the interleaved power supply 1, and the main switch control circuit 200 according to the first embodiment According to the control circuits 100a, 100b and the interleaved power supply 1 of the first embodiment, the control circuit can switch between an interleaved transmission mode in which an interleaved operation is performed and an input voltage monitoring mode in which the input voltage is monitored, so that the input voltage can be monitored by the slave converter 40, not the main converter 20. Therefore, it is not necessary to provide new terminals to the main switch control circuit 200, which already has many terminals. Therefore, it is possible to provide an interleaved power supply that can monitor the input voltage without increasing the number of terminals of the main switch control circuit 200.

[0084] Furthermore, according to the control circuits 100a, 100b and interleaved power supply 1 of embodiment 1, the mode determination unit 140 acquires input voltage information and determines whether the mode is the interleaved transmission mode or the input voltage monitoring mode based on the input voltage information, and therefore has an input voltage monitoring function that monitors the input voltage and stops the main converter 20 when the input voltage falls below a predetermined voltage.

[0085] Furthermore, according to the control circuits 100a, 100b and interleaved power supply 1 of embodiment 1, when the mode determination unit 140 determines that the mode is the interleave transmission mode, an interleave signal transmission signal is output to the interleave control unit 120, so that interleave operation can be performed.

[0086] Furthermore, according to the control circuits 100a, 100b and the interleaved power supply 1 of the first embodiment, since the control circuits 100a and 100b use circuits of the same configuration, it is not necessary to prepare different control circuits for the control circuits 100a of the slave converters 30 other than the final stage and the control circuit 100b of the slave converter 40 of the final stage. Therefore, it is not necessary to design and produce separate control circuits, resulting in a highly versatile control circuit.

[0087] Furthermore, according to the control circuits 100a, 100b and the interleaved power supply 1 of the first embodiment, when the mode determination unit 140 determines that the input voltage monitoring mode is selected, the mode determination unit 140 outputs an input voltage monitoring mode detection signal to the main converter control signal generation unit 160, and the main converter control signal generation unit 160 determines whether to maintain or stop the operation of the main converter 20 based on the input voltage monitoring mode detection signal, so that the input voltage monitoring mode can be realized by the control circuit 100b. Even in the input voltage monitoring mode, it is possible to determine whether to maintain or stop the operation of the main converter 20 based on the input voltage monitoring mode detection signal (the voltage at the VIS terminal), so that the PFC operation can be maintained as long as possible, and the performance of the interleaved power supply can be maintained as long as possible.

[0088] Furthermore, according to the control circuits 100a, 100b and the interleaved power supply 1 of the first embodiment, when it is determined that the operation of the main converter 20 should be maintained, the main converter control signal generating unit 160 sets the interleaved output terminal IL_OUT to an open state, thereby cutting off the connection with the main converter 20 and not impeding the operation of the main converter 20. Furthermore, when it is determined that the operation of the main converter 20 should be stopped, the main converter control signal generating unit 160 outputs a main converter stop signal, thereby making it possible to stop the PFC operation of the interleaved power supply as necessary.

[0089] Furthermore, according to the control circuits 100a, 100b and interleaved power supply 1 of embodiment 1, when the mode determination unit 140 determines that the interleaved transmission mode is selected, and when the main converter control signal generation unit 160 determines that the operation of the main converter 20 is to be stopped, the change-over switch 170 is turned on, and when the main converter control signal generation unit 160 determines that the operation of the main converter 20 is to be maintained, the change-over switch 170 is turned off. Therefore, the change-over switch 170 can be turned off when there is no need to transmit a signal to prevent it from affecting other converters.

[0090] Furthermore, according to the control circuits 100a, 100b and interleaved power supply 1 of embodiment 1, when the input voltage monitoring mode detection signal (voltage at the VIS terminal) becomes lower than a predetermined threshold, the main converter control signal generating unit 160 determines that the operation of the main converter 20 should be stopped and outputs a main converter stop signal; otherwise, the output terminal is set to an open state, so that no new terminal is added for controlling the operation of the main converter 20.

[0091] Furthermore, with the interleaved power supply 1 according to the first embodiment, when the slave converter farthest from the main converter among a plurality of slave converters is set as the final stage slave converter 40, the final stage slave converter 40 operates in an input voltage monitoring mode that monitors the input voltage based on input voltage information, while the slave converters 30 other than the final stage operate in an interleave transmission mode that performs interleaved operation, so that not only can the multiple stages of slave converters perform interleaved operation, but the function of monitoring the input voltage can also be shared. Also, since the final stage slave converter does not need to output from the IL_OUT terminal, the final stage slave converter can be provided with the function of monitoring the input voltage.

[0092] Furthermore, according to the interleaved power supply 1 of the first embodiment, a main converter stop signal from a control circuit (control circuit 100b) that controls the switching operation of the slave switch 42 is input to an FB terminal (feedback terminal) of the main switch control circuit 200, and whether or not to stop the main converter 20 is determined based on the voltage input to the FB terminal (feedback terminal), so that the feedback terminal already provided for detecting overcurrent, etc. can be utilized to realize the input voltage monitoring function. Therefore, since a part of the circuit can be shared with the existing protection function, the input voltage monitoring function can be realized without adding a new terminal or making a major change to the circuit.

[0093] Furthermore, according to the interleaved power supply 1 of the first embodiment, the main switch control circuit 200 stops the interleaving operation when the COMP voltage, which is the error amplifier output voltage generated by the voltage based on the output voltage, falls below a predetermined threshold, so that the PFC operation can be maintained from when the COMP voltage starts to drop until it falls below the threshold. Therefore, it is possible to maintain the PFC operation as long as possible. In addition, the above configuration has the effect of preventing the ON width from suddenly becoming too wide when the input voltage becomes high again, thereby preventing the occurrence of noise and the like.

[0094] Furthermore, according to the main switch control circuit 200 of the first embodiment, when a main converter stop signal is output from the control circuit (control circuit 100b) that controls the switching operation of the slave switch, the main converter stop signal is input to the feedback terminal FB, and the voltage monitoring unit 220 determines whether or not to stop the main converter 20 based on the main converter stop signal input to the feedback terminal FB, so that, for example, it is possible to determine whether or not to stop the main converter by inputting the main converter stop signal from the control circuit 100b to the feedback terminal FB that monitors whether the output voltage is an overvoltage or changes the on width of the main switch. As a result, there is no need to provide a new terminal for inputting the main converter stop signal.

[0095] [Embodiment 2] The interleaved power supply 2 of embodiment 2 basically has the same configuration as the interleaved power supply 1 of embodiment 1, but differs from the interleaved power supply 1 of embodiment 1 in that it has a switch 23 between the FB terminal of the main switch control circuit 200 and the IL_OUT terminal of the control circuit 100b (see Figure 6).

[0096] The switch 23 has a gate electrode connected to the IL_OUT terminal of the control circuit 100b, and when the switch 23 receives a signal from the IL_OUT terminal, the switch 23 turns on and a predetermined voltage is input to the FB terminal.

[0097] Thus, the interleaved power supply 2 according to the second embodiment is different from the interleaved power supply 1 according to the first embodiment in that it has a switch 23 between the FB terminal of the main switch control circuit 200 and the IL_OUT terminal of the control circuit 100b. However, as in the case of the interleaved power supply 1 according to the first embodiment, the control circuits 100a and 100b can switch between an interleaved transmission mode in which an interleaved operation is performed and an input voltage monitoring mode in which the input voltage is monitored, so that the input voltage can be monitored by the slave converter, not the main converter. Therefore, it is not necessary to provide new terminals to the main switch control circuit, which already has many terminals. Therefore, it is possible to provide an interleaved power supply that can monitor the input voltage without increasing the number of terminals of the main switch control circuit.

[0098] Furthermore, according to the interleaved power supply 2 of the second embodiment, since the IL_OUT terminal of the control circuit 100b and the FB terminal of the main switch control circuit 200 are not directly connected, and even if a relatively large amount of noise is mixed between the IL_OUT terminal of the control circuit 100b and the FB terminal of the main switch control circuit 200, the switch 23 can prevent the noise from being mixed directly into the FB terminal of the main switch control circuit 200 and causing a malfunction in the main switch control circuit 200. As a result, the interleaved power supply is even less susceptible to the effects of noise.

[0099] The interleaved power supply 2 of embodiment 2 has the same configuration as the interleaved power supply 1 of embodiment 1 except that it has a switch 23 between the FB terminal of the main switch control circuit 200 and the IL_OUT terminal of the control circuit 100b, and therefore has the corresponding effects among the effects of the interleaved power supply 1 of embodiment 1.

[0100] Although the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment. It can be embodied in various forms without departing from the spirit of the present invention, and for example, the following modifications are also possible.

[0101] (1) The positions, connections, quantities, etc. described in the above embodiments (including the modified examples; the same applies below) are merely examples and may be changed without impairing the effects of the present invention.

[0102] (2) In each of the above embodiments, the main converter has an output overvoltage detection function and a low input voltage detection function, but the present invention is not limited to this. The main converter does not have to have either or both of the output overvoltage detection function and the low input voltage detection function.

[0103] (3) In the above embodiments, the method of detecting the inductor current is to detect the drain current of the main switch 22 and detect the timing when the current becomes zero, but the present invention is not limited to this. As a method of detecting the inductor current, a detection winding may be provided in the inductor, and the timing when the current becomes zero may be detected by detecting the current flowing through the detection winding.

[0104] (4) In each of the above embodiments, it is determined whether to maintain or stop the operation of the main converter in the input voltage monitoring mode, but the present invention is not limited to this. It is also possible not to maintain the operation of the main converter without determining whether to maintain or stop the operation of the main converter in the input voltage monitoring mode.

[0105] (5) In each of the above embodiments, a changeover switch is provided, but the present invention is not limited to this. A changeover switch does not have to be provided. Also, although an internal MOS is used as the changeover switch, other suitable switching elements or switches may be used. [Explanation of symbols]

[0106] 1, 2... interleaved power supply, 20... main converter, 22... main switch, 30, 40... slave converter, 32, 42... slave switch, 100a, 100b... control circuit, 110... interleave signal input section, 120... interleave control section, 130... drive section, 140... mode determination section, 150... interleave output signal generation section, 160... main converter control signal generation section, 170... changeover switch, 200... main switch control circuit, 220... voltage monitoring section FB: Feedback terminal

Claims

1. A control circuit for controlling the switching operation of the slave switch for an interleaved power supply comprising: a main converter having a main switch that performs a switching operation; and a slave converter having a slave switch that performs switching with a predetermined phase difference with respect to the switching operation of the main switch, the control circuit comprising: The control circuit is characterized in that it comprises an interleave signal input unit, an interleave control unit, a drive unit, an interleave output signal generation unit, and a mode determination unit, and is capable of switching between an interleave transmission mode that performs interleave operation and an input voltage monitoring mode that monitors the input voltage.

2. The interleave signal input unit acquires an interleave input signal input from the main converter or another of the slave converters, and outputs on-width information generated based on the interleave input signal to the interleave control unit; the interleave control unit outputs a control signal to the drive unit for turning on and off the slave switch at a timing adjusted based on the on-width information, and when an interleave signal transmission signal is input, outputs interleave output information generated based on the on-width information to the interleave output signal generation unit; The drive unit turns on and off the slave switch based on the control signal, the interleaved output signal generator generates an interleaved output signal based on the interleaved output information; the mode determination unit acquires input voltage information, and determines whether the mode is the interleaved transfer mode or the input voltage monitoring mode based on the input voltage information; 2. The control circuit according to claim 1, wherein when the mode determination unit determines that the interleave transfer mode is selected, the control circuit outputs an interleave signal transfer signal to the interleave control unit.

3. The control circuit further includes a main converter control signal generating unit, When the mode determination unit determines that the input voltage monitoring mode is selected, the mode determination unit outputs an input voltage monitoring mode detection signal to the main converter control signal generation unit; 3. The control circuit according to claim 1, wherein the main converter control signal generating unit determines whether to maintain or stop the operation of the main converter based on the input voltage monitoring mode detection signal.

4. 4. The control circuit according to claim 3, wherein the main converter control signal generating unit determines to stop operation of the main converter when the input voltage monitoring mode detection signal is lower than a predetermined threshold, and determines to maintain operation of the main converter when the input voltage monitoring mode detection signal is higher than a predetermined threshold.

5. The control circuit according to claim 3, characterized in that the main converter control signal generating unit outputs a main converter stop signal when it determines that the operation of the main converter is to be stopped, and sets an output terminal to an open state when it determines that the operation of the main converter is to be maintained.

6. The control circuit further includes a changeover switch connected between the main converter control signal generating unit and an output terminal and between the interleaved output signal generating unit and an output terminal; When the mode determination unit determines that the mode is the interleaved transmission mode, and when the main converter control signal generation unit determines that the operation of the main converter is to be stopped in the input voltage monitoring mode, the changeover switch is turned on, 5. The control circuit according to claim 4, wherein when the main converter control signal generating unit determines to maintain operation of the main converter in the input voltage monitoring mode, the changeover switch is turned off.

7. a main converter having a main switch that performs a switching operation; a slave converter having a slave switch that switches with a predetermined phase difference with respect to the switching operation of the main switch, A master-slave relationship is formed between the master converter and the slave converter, The main converter has a main switch control circuit that controls a switching operation of the main switch, 3. An interleaved power supply, wherein the slave converter comprises the control circuit according to claim 1 or 2 as a control circuit for controlling a switching operation of the slave switch.

8. The slave converter includes a plurality of slave converters, The interleaved power supply of claim 7, characterized in that among the multiple slave converters, the final stage slave converter, which is the slave converter farthest from the main converter, operates in an input voltage monitoring mode that monitors the input voltage based on input voltage information, and the slave converters other than the final stage slave converter operate in an interleaved transmission mode that performs interleaved operation.

9. The main switch control circuit includes: A feedback terminal for inputting a voltage based on the output voltage; a voltage monitoring unit that monitors a voltage input to the feedback terminal; When a main converter stop signal is output from a control circuit that controls a switching operation of the slave switch, the main converter stop signal is input to the feedback terminal, 8. The interleaved power supply according to claim 7, wherein the voltage monitoring unit determines whether or not to shut down the main converter based on the main converter shut down signal input to the feedback terminal.

10. The interleaved power supply according to claim 9, characterized in that the main switch control circuit stops the main converter when an error amplifier output voltage generated by the voltage input to the feedback terminal becomes equal to or lower than a predetermined threshold value.

11. A main switch control circuit for an interleaved power supply including a main converter having a main switch that performs a switching operation, and a slave converter having a slave switch that performs switching with a predetermined phase difference with respect to the switching operation of the main switch, the main switch control circuit controlling the switching operation of the main switch for an interleaved power supply in which a master-slave relationship is formed between the main converter and the slave converter, A feedback terminal for inputting a voltage based on the output voltage; a voltage monitoring unit that monitors a voltage based on an output voltage input to the feedback terminal, When a main converter stop signal is output from a control circuit that controls a switching operation of the slave switch, the main converter stop signal is input to the feedback terminal, The main switch control circuit is characterized in that the voltage monitoring unit determines whether or not to stop the main converter based on the main converter stop signal input to the feedback terminal.

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