Power IC and power circuit

Abstract

The present application provides power IC and power supply circuit. Can improve the efficiency of power supply and reduce the generation of noise, can reduce the cost. Power supply circuit (10) contains: pulse generation part (200), which generates the working pulse that makes the switching element (Q1, Q2) on / off; Voltage detection part (300) detects the output voltage (Vswo) of the arm part (100) with switching element (Q1, Q2); And the control part (400) controls the pulse generation part (200) according to the voltage level detected by the voltage detection part (300), the control part (400) makes the pulse generation part (200) generate the working pulse (PW1) with pulse width (Tpw1) according to the voltage level detected by the voltage detection part (300), then makes the pulse generation part (200) generate the working pulse (PW2) with pulse width (Tpw2) longer than the pulse width (Tpw1) of the working pulse (PW1), and generates the working pulse (PW2) in a way that contains the working pulse (PW1) to be at least 3 or more odd.

Description

Technical Field

[0001] This disclosure relates to power supply ICs and power supply circuits. Background Technology

[0002] Typically, power supply circuits used in various devices require high efficiency and low noise.

[0003] In switching power supplies that can achieve high-efficiency power, there exists a case where, after generating a rectangular wave by alternately switching the high-side and low-side switching elements, a resonant DC-DC converter circuit is constructed to generate the required DC voltage by setting up a resonant circuit and a rectifier circuit.

[0004] Regarding resonant DC-DC converter circuits, when the load becomes lighter, the efficiency of voltage conversion sometimes decreases due to the increase in circulating current.

[0005] Therefore, by turning the resonant DC-DC converter circuit on (ON) / off (OFF), the efficiency of voltage conversion is improved.

[0006] At this time, the following noises may be generated in the resonant DC-DC converter circuit: noise generated near the audible frequency band due to the sound produced by the switching frequency; or radiated noise caused by the high harmonics of the resonant circuit or the peak waveform.

[0007] In such cases, the power supply circuit needs to reduce the noise level to a level where the generated noise does not affect the performance of the device.

[0008] As a means to solve the above-mentioned requirements, the following technology is disclosed: In a resonant DC-DC converter circuit, a starting pulse that turns on the low-side switching element, a main pulse that turns on the high-side switching element, and an ending pulse that turns on the switching element are constituted. When the burst period is close to the period of a frequency close to the upper limit of the audible frequency band, the second disconnection threshold voltage of the main pulse is set to be the same as the first disconnection threshold voltage of the starting pulse, thereby shortening the on-time of the main pulse (for example, see Patent Document 1).

[0009] Patent Document 1: Japanese Patent No. 7040542

[0010] The technology shown in Patent Document 1 is as follows: when the burst period is close to the upper limit of the audible frequency band, the second disconnect threshold voltage of the main pulse is set to be the same as the first disconnect threshold voltage of the starting pulse, thereby shortening the on-width of the main pulse and preventing the burst period from entering the audible frequency band and producing sound during the burst control of the resonant converter.

[0011] However, in the burst control device of the resonant converter described in Patent Document 1, for example, according to the timing of the switch consisting of 3 pulses, spike noise is generated, the higher harmonics of the spike noise become radiated noise and generate noise, and switching losses are also generated.

[0012] Moreover, the following problems exist: due to the generated radiated noise, the equipment equipped with this power supply may malfunction, or may radiate noise towards the outside of the equipment. Summary of the Invention

[0013] Therefore, this disclosure was made in view of the above-mentioned issues, and its object is to provide a power supply IC and power supply circuit that improves power supply efficiency, reduces noise generation, and lowers cost.

[0014] One or more embodiments of the present invention provide a power supply IC and power supply circuit in the form of a resonant converter, which control a plurality of switching elements, wherein the power supply IC and power supply circuit include: a pulse generation unit that generates operating pulses to turn the switching elements on / off; a voltage detection unit that detects the output voltage of the switching elements; and a control unit that controls the pulse generation unit according to the voltage level detected by the voltage detection unit, wherein the control unit causes the pulse generation unit to generate a first operating pulse having a first pulse width according to the voltage level detected by the voltage detection unit, and then causes the pulse generation unit to generate a second operating pulse with a pulse width longer than the pulse width of the first operating pulse, in an odd number of pulses including at least three.

[0015] According to one or more embodiments of this disclosure, a power supply IC and power supply circuit can be provided that improves power supply efficiency, reduces noise generation, and lowers cost. Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating a power supply circuit according to a first embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram showing details of the power supply circuit according to the first embodiment of the present invention.

[0018] Figure 3 This is a timing diagram of the switching element, voltage detection unit, control unit, and pulse generation unit in the first embodiment of the present invention.

[0019] Figure 4 This is a block diagram illustrating a power supply circuit according to a second embodiment of the present invention.

[0020] Figure 5This is a schematic diagram showing details of the power supply circuit according to a second embodiment of the present invention.

[0021] Figure 6 This is a timing diagram of the switching element, voltage detection unit, control unit, and pulse generation unit in the second embodiment of the present invention.

[0022] Label Explanation

[0023] 10: Power supply circuit;

[0024] 100: Arm;

[0025] 200: Pulse generation unit;

[0026] 300: Voltage detection unit;

[0027] 400: Dominance Department;

[0028] 400A: Dominance Department;

[0029] 410: Delay section;

[0030] 420: Control Unit;

[0031] 420A: Control Unit;

[0032] 430: Counting section;

[0033] 440: Timing Department;

[0034] 500: Resonant circuit section;

[0035] 600: Voltage conversion unit;

[0036] 700: Rectifier circuit section;

[0037] 800: Output detection unit;

[0038] DS: Delayed signal;

[0039] Q1: Switching element (high side);

[0040] Q2: Switching element (low side);

[0041] PW1: Working pulse;

[0042] PW2: Working pulse;

[0043] Tpw1: Pulse width;

[0044] Tpw2: Pulse width. Detailed Implementation

[0045] use Figures 1 to 6 The power supply circuit 10 and power supply circuit 10A of this embodiment will be described.

[0046] <First Implementation Method>

[0047] The following uses Figures 1 to 3 The power supply circuit 10 of this embodiment will be described.

[0048] In addition, the power supply IC1 is configured to include a power supply circuit 10.

[0049] <Structure of Power Supply Circuit 10>

[0050] The power supply circuit 10 is, for example, a power supply based on a resonant DC-DC converter circuit, which generates a stable output voltage Vout by voltage conversion of the input voltage Vin.

[0051] like Figure 1 As shown, the power supply circuit 10 is configured to include an arm section 100, a pulse generation section 200, a voltage detection section 300, a control section 400, a resonant circuit section 500, a voltage conversion section 600, and a rectifier circuit section 700.

[0052] (Regarding arm 100)

[0053] Regarding the arm 100, such as Figure 2 As shown, for example, as multiple switching elements, a switching element Q1 is provided on the high side and a switching element Q2 is provided on the low side.

[0054] Here, the switching elements Q1 and Q2 are, for example, FETs such as MOSFETs.

[0055] The following example illustrates the case where switching elements Q1 and Q2 are constructed using FETs.

[0056] The drain terminal Q1d of the switching element Q1 constituting the arm 100 is connected to the input voltage Vin, and the source terminal Q1s is connected to the drain terminal Q2d of the switching element Q2, forming the output terminal SWO of the arm 100.

[0057] A capacitor C1 is connected between the drain terminal Q1d of the switching element Q1 and GND.

[0058] The gate terminal Q1g of the switching element Q1 is connected to Q1out in the pulse generation unit 200.

[0059] The source terminal Q2s of the switching element Q2 is connected to GND, and the gate terminal Q2g is connected to Q2out in the pulse generation unit 200.

[0060] The ON / OFF state of switching elements Q1 and Q2 is controlled by operating pulses PW1 and PW2 input to the gate terminal Q1g of switching element Q1 and the gate terminal Q2g of switching element Q2.

[0061] Working pulses PW1 and PW2 are output from pulse generation unit 200 based on information sent from control unit 400.

[0062] (Regarding pulse generation unit 200)

[0063] The pulse generation unit 200 generates working pulses PW1 and PW2 to turn on / off the switching elements Q1 and Q2.

[0064] The pulse generation unit 200 is connected to the gate terminal Q1g of the switching element Q1, the gate terminal Q2g of the switching element Q2, and the control unit 400 in the arm 100.

[0065] The pulse generation unit 200 generates, for example, a working pulse PW1 having a pulse width Tpw1 as a first pulse width and a working pulse PW2 having a pulse width Tpw2 as a second pulse width based on information from the control unit 400.

[0066] Then, the pulse generation unit 200 outputs from the output terminal Q1out or the output terminal Q2out to the gate terminal Q1g of the switching element Q1 or the gate terminal Q2g of the switching element Q2.

[0067] like Figure 3 (a) and Figure 3 As shown in (b), the pulse generation unit 200 takes the working pulse PW1 at the output terminal Q1out and the working pulse PW1 in the next cycle as a cycle, and repeatedly generates working pulse PW1 and working pulse PW2.

[0068] (Regarding voltage detection unit 300)

[0069] The voltage detection unit 300 detects the output voltage Vswo of the output terminal SWO of the arm 100 as the voltage level.

[0070] like Figure 2 As shown, the input terminal DTin of the voltage detection unit 300 is connected to the output terminal SWO in the arm 100.

[0071] The voltage detection unit 300 is, for example, composed of a comparator circuit, and the reference voltage of the comparator circuit is set to the threshold voltage Vref.

[0072] The voltage detection unit 300 determines whether the output voltage Vswo has reached the preset threshold voltage Vref, and outputs the determination result as the resonant voltage signal Vs to the control unit 400.

[0073] For example, such as Figure 3 As shown in (d), the resonant voltage signal Vs is output as a pulse wave.

[0074] Regarding the resonant voltage signal Vs, for example, Hi is output when the output voltage Vswo reaches the threshold voltage Vref, and Lo is output when the output voltage Vswo does not reach the threshold voltage Vref.

[0075] (Regarding Department 400)

[0076] The control unit 400 controls the pulse generation unit 200 based on the output voltage Vswo, which is the voltage level detected by the voltage detection unit 300.

[0077] like Figure 2 As shown, the control unit 400 is connected to the pulse generation unit 200 and the voltage detection unit 300.

[0078] The control unit 400 is configured to include a delay unit 410, a control unit 420, and a counting unit 430.

[0079] The delay unit 410 is connected to the voltage detection unit 300 and the control unit 420.

[0080] like Figure 3 As shown in (e), the delay unit 410 receives the resonant voltage signal Vs output from the voltage detection unit 300 and causes a time delay T2 (delay time) during which the output voltage Vswo changes from the threshold voltage Vref to the switching threshold voltage Vsw.

[0081] The time T2 mentioned here is, for example, a time preset based on the resonance set by the resonant circuit section 500, which is set to the time when the potential difference between the output voltage Vswo and the input voltage Vin becomes the minimum.

[0082] Regarding the delayed signal DS output from the delay unit 410, for example, when the resonant voltage signal Vs is Hi, Hi is output after a delay time T2, and when the resonant voltage signal Vs is Lo, Lo is output after a delay time T2.

[0083] like Figure 2 As shown, the control unit 420 is connected to the pulse generation unit 200, the delay unit 410, the counting unit 430, and the output detection unit 800.

[0084] Based on information from the delay unit 410 and the counting unit 430, the control unit 420 controls the switching elements Q1 and Q2 to be turned on / off via the pulse generation unit 200.

[0085] Specifically, the control unit 420 controls the pulse generation unit 200 based on information from the delay unit 410 and the counting unit 430, so that the switching elements Q1 and Q2 output working pulse PW1 or working pulse PW2.

[0086] The control unit 420 corrects the pulse widths of the working pulse PW1 (Tpw1) and the working pulse PW2 (Tpw2) based on information about the output voltage Vout sent from the output detection unit 800, which will be described later.

[0087] Specifically, the control unit 420 determines, for example, whether the output voltage Vout is higher or lower than a predetermined threshold based on information from the output detection unit 800.

[0088] When the control unit 420 determines that the output voltage Vout is higher than a predetermined threshold, the control unit 420 sends information to the pulse generation unit 200 instructing to shorten the pulse width Tpw1 and pulse width Tpw2 by the same ratio.

[0089] In addition, when the control unit 420 determines that the output voltage Vout is lower than a specified threshold, the control unit 420 sends information to the pulse generation unit 200 instructing to extend the pulse width Tpw1 and pulse width Tpw2 by the same ratio.

[0090] The counting unit 430 is connected to the pulse generation unit 200 and the control unit 420.

[0091] The counting unit 430 counts the number of working pulses output from the pulse generation unit 200 and outputs the counted number of working pulses to the control unit 420.

[0092] Specifically, the counting unit 430 counts, for example, the number of working pulses PW1 and PW2 output from the pulse generation unit 200 to the switching elements Q1 and Q2.

[0093] The counting unit 430 outputs information related to the number of pulses of the working pulses PW1 and PW2 to the control unit 420.

[0094] (Regarding the resonant circuit section 500)

[0095] like Figure 2 As shown, the resonant circuit section 500 is connected to the output terminal SWO of the arm section 100.

[0096] The resonant circuit section 500 is, for example, composed of the primary coil L1 and capacitor C2 in the voltage conversion section 600.

[0097] One end of the primary coil L1 is connected to the output terminal SWO, and the other end of the primary coil L1 is connected to one end of the capacitor C2.

[0098] The other end of capacitor C2 is connected to GND.

[0099] The output voltage Vswo, output to the output terminal SWO, passes through the primary coil L1 in the voltage conversion unit 600 and the capacitor C2 connected to the primary coil L1. Figure 3 The residual resonant voltage waveform during time T1 is shown in (c), and then gradually decays.

[0100] (Regarding voltage conversion unit 600)

[0101] The voltage conversion unit 600 converts the voltage input to the primary side and outputs it to the secondary side.

[0102] The voltage conversion unit 600 is, for example, a transformer that converts the input voltage based on the ratio of the primary winding L1 to the secondary winding L2.

[0103] The output terminal SWO of the arm 100 and the input terminal DTin of the voltage detection unit 300 are connected to the primary side of the voltage conversion unit 600.

[0104] A rectifier circuit section 700 is connected to the secondary side of the voltage conversion section 600.

[0105] (Regarding the rectifier circuit section 700)

[0106] The rectifier circuit 700 generates an output voltage Vout by smoothing the voltage output from the voltage conversion unit 600.

[0107] The rectifier circuit section 700 is, for example, composed of a secondary coil L2, rectifier diodes D1 and D2, and a capacitor C3.

[0108] One end of the secondary coil L2 is connected to the anode of the rectifier diode D1, and the other end of the secondary coil L2 is connected to the anode of the rectifier diode D2.

[0109] The cathodes of rectifier diodes D1 and D2 are connected to the anode of capacitor C3 and to the anode of the output voltage Vout.

[0110] The midpoint of the secondary coil L2 is connected to the cathode of capacitor C3 and to the cathode of the output voltage Vout.

[0111] The rectifier circuit 700 is rectified by the rectifier diodes D1 and D2 of the secondary coil L2, and smoothed by the secondary coil L2 and capacitor C3 to generate the output voltage Vout.

[0112] (Regarding the output detection unit 800)

[0113] The output detection unit 800 detects the output voltage Vout generated in the rectifier circuit unit 700 and sends information related to the output voltage Vout to the control unit 400.

[0114] The output detection unit 800 is connected to the control unit 420 in the control unit 400, the anode of the capacitor C3 in the rectifier circuit unit 700, and the cathode of the capacitor C3.

[0115] <Functions and Effects>

[0116] use Figure 2 and Figure 3 The function and effects of the power supply circuit 10 of this embodiment, configured as described above, will be explained.

[0117] like Figure 3 (a) and Figure 3 As shown in (b), when the control unit 400 obtains information indicating that the output voltage Vswo has become the switching threshold voltage Vsw, it outputs a working pulse PW1 to the switching element Q1 via the pulse generation unit 200.

[0118] Therefore, the switching element Q1 is turned on by the working pulse PW1, and turns off after the output voltage Vswo is output during the pulse width Tpw1 of the working pulse PW1.

[0119] Here, when the switching element Q1 switches from off to on, a potential difference VQ1ds is generated between the drain terminal Q1d and the source terminal Q1s of the switching element Q1, and the current value increases instantaneously, thereby generating spike noise in the output voltage Vswo of arm 100.

[0120] Specifically, there is a parasitic capacitance CQ1ds (not shown) between the drain terminal Q1d and the source terminal Q1s in the switching element Q1.

[0121] If the switching element Q1 is turned on when a potential difference VQ1ds is generated between the drain terminal Q1d and the source terminal Q1s, a switching loss P will be generated between the drain terminal Q1d and the source terminal Q1s.

[0122] The resulting switching loss P is calculated using the following Equation 1.

[0123] [Formula 1]

[0124]

[0125] When the potential difference VQ1ds and current between the drain terminal Q1d and the source terminal Q1s change rapidly, resonance occurs due to the parasitic capacitance CQ1ds and the inductance of the wiring, resulting in spike noise in the switching element Q1.

[0126] Therefore, the control unit 400 turns on the switching element Q1 when the potential difference VQ1ds is small, thereby minimizing the spike noise caused by the potential difference between the drain terminal Q1d and the source terminal Q1s.

[0127] Furthermore, by turning on the switching element Q1 when the potential difference VQ1ds is small, the control unit 400 minimizes the switching loss P.

[0128] Specifically, for example, such as Figure 3 As shown in (d), the delay unit 410 in the control unit 400 acquires the time when the resonant voltage signal VS exceeds the threshold voltage Vref based on the resonant voltage signal VS output from the voltage detection unit 300.

[0129] like Figure 3 As shown in (e), the delay unit 410 sends information to the control unit 420 indicating the delay time T2 after the resonant voltage signal VS exceeds the threshold voltage Vref.

[0130] Then, as Figure 3 As shown in (a), the control unit 420 turns on the switching element Q1 via the pulse generation unit 200 based on the information from the delay unit 410.

[0131] Next, as Figure 3 As shown in (b), the control unit 400 outputs a working pulse PW2 to the switching element Q2 via the pulse generation unit 200.

[0132] At this time, as Figure 3 As shown in (c), the switching element Q2 is turned on by the working pulse PW2, and turns off after the output voltage Vswo becomes GND level during the pulse width Tpw2 of the working pulse PW2.

[0133] Furthermore, such as Figure 3 As shown in (a), the control unit 400 outputs a working pulse PW2 to the switching element Q1 via the pulse generation unit 200.

[0134] In this case, the switching element Q1 is turned on by the working pulse PW2, and turns off after outputting a voltage to the output voltage Vswo during the pulse width Tpw2 of the working pulse PW2.

[0135] As described above, the control unit 400 outputs a working pulse PW1 to the switching element Q1, then outputs a working pulse PW2 to the switching element Q2, and then outputs a working pulse PW2 to the switching element Q1. As a result, the output voltage Vswo at the output terminal SWO is increased while improving the efficiency of the power supply.

[0136] The control unit 400 controls the number of pulses of working pulses PW1 and PW2 via the pulse generation unit 200 based on the information related to the number of pulses of working pulses PW1 and PW2 output from the counting unit 430.

[0137] In other words, the control unit 400 causes the high-voltage side switching element Q1 to output the working pulse PW2 as the last working pulse, thereby making the output voltage Vswo retain a voltage above the switching threshold voltage Vsw.

[0138] Therefore, the control unit 400 outputs an even number of working pulses PW2.

[0139] Therefore, the control unit 400 generates working pulse PW2 in an odd number of times, including working pulse PW1, which is at least three.

[0140] At this time, the output voltage Vswo becomes a voltage above the switching threshold voltage Vsw, and thus the potential difference VQ1ds becomes relatively small.

[0141] Furthermore, the control unit 400 turns on the switching element Q1 when the potential difference VQ1ds is small, thereby minimizing spike noise and switching loss P.

[0142] In addition, when the switching frequency of switching elements Q1 and Q2 is high, in order to adjust the output voltage Vout, the control unit 400 stops the switching of switching elements Q1 and Q2 during time T1.

[0143] Specifically, for example, such as Figure 3 (a) and Figure 3 As shown in (b), during time T1, the control unit 400 repeatedly generates working pulses PW1 and PW2 while the switching elements Q1 and Q2 are stopped.

[0144] In other words, the control unit 400 generates working pulses PW1 and PW2 repeatedly at a frequency F that is one cycle between working pulse PW1 and the next working pulse PW1, or between working pulse PW2 and the next working pulse PW2.

[0145] At this time, since the frequency F of one cycle becomes an audible frequency, audible noise may sometimes be generated from the voltage conversion unit 600, for example.

[0146] Therefore, the control unit 400 causes the pulse generation unit 200 to generate working pulses PW1 and PW2 in such a way that the number of times the switching elements Q1 and Q2 are turned on / off is reduced to the necessary minimum, wherein the working pulse PW2 is generated in such a way that there are 3 working pulses including working pulse PW1.

[0147] Furthermore, by minimizing the number of times the switching elements Q1 and Q2 are turned on / off, the control unit 400 suppresses audible noise.

[0148] Furthermore, by suppressing audible band noise, the power supply IC1 and power supply circuit 10 can reduce the cost of reducing audible band noise.

[0149] Furthermore, the control unit 400 sets the pulse width Tpw1 of the working pulse PW1 in such a way that after the last working pulse PW2 is applied to the switching element Q1 of the FET which is the high side via the pulse generation unit 200, the desired level of vibration between the drain and source of the switching element Q2 of the FET which is the low side remains as the output voltage Vswo during the time period T1 which is a predetermined period.

[0150] Specifically, such as Figure 3 As shown in (c), by turning the arm 100 on / off, a resonant vibration wave is generated in the output voltage Vswo based on the resonant characteristics set in the resonant circuit section 500 described later, and the vibration voltage remains.

[0151] The control unit 420 sends an instruction to the pulse generation unit 200 to adjust the pulse width Tpw1 and pulse width Tpw2 by the same ratio based on information related to the output voltage Vout from the output detection unit 800.

[0152] Since the primary coil L1 and capacitor C2 in the resonant circuit section 500 are preset fixed values, the control section 400 adjusts the pulse width Tpw1 of the working pulse PW1 based on the information from the output detection section 800, thereby allowing the output voltage Vswo to remain during the time T1.

[0153] As explained above, the power supply circuit 10 of this embodiment is a resonant converter-type power supply circuit 10 having multiple switching elements Q1 and Q2, and includes: a pulse generation unit 200 that generates working pulses PW1 and PW2 to turn the switching elements Q1 and Q2 on / off; a voltage detection unit 300 that detects the output voltage Vswo of the arm 100; and a control unit 400 that controls the pulse generation unit 200 based on the output voltage Vswo detected by the voltage detection unit 300 as a voltage level. The control unit 400, based on the output voltage Vswo detected by the voltage detection unit 300, causes the pulse generation unit 200 to generate a working pulse PW1 with a pulse width Tpw1 as a first pulse width, and then causes the pulse generation unit 200 to generate a working pulse PW2 with a pulse width Tpw2 longer than the pulse width of the working pulse PW1, as a second working pulse, and generates the working pulse PW2 in an odd number of at least three, including the working pulse PW1.

[0154] That is, when the control unit 400 obtains information indicating that the output voltage Vswo has become the switching threshold voltage Vsw, it outputs a working pulse PW1 to the switching element Q1 via the pulse generation unit 200.

[0155] At this time, regarding the switching threshold voltage Vsw, when the potential difference VQ1ds between the input voltage Vin supplied to the switching element Q1 and the output voltage Vswo is small, the control unit 400 detects the switching threshold voltage Vsw via the voltage detection unit 300 and the delay signal DS of the delay unit 410.

[0156] The control unit 400 turns on the switching element Q1 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, thereby minimizing the generation of spike noise.

[0157] Furthermore, the control unit 400 causes the pulse generation unit 200 to output a working pulse PW1 to the switching element Q2 after outputting a working pulse PW1 to the switching element Q1.

[0158] Then, the control unit 400 causes the pulse generation unit 200 to output a working pulse PW2 to the switching element Q1, thereby increasing the output voltage Vswo of the output terminal SWO of the arm 100.

[0159] At this time, the control unit 400 outputs an even number of working pulses PW2 toward the switching element Q2 and working pulses PW2 toward the switching element Q1.

[0160] In other words, the control unit 400 generates the working pulse PW2 in an odd number of at least three, including the working pulse PW1, thereby leaving the output voltage Vswo.

[0161] Therefore, the control unit 400 turns on the switching element Q1 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, so as to minimize the generation of spike noise and thus minimize the radiated noise emitted toward the outside of the device.

[0162] Furthermore, by turning on the switching element Q1 when the potential difference VQ1ds is small, the control unit 400 can minimize the switching loss P.

[0163] Furthermore, the control unit 400 generates the working pulse PW2 in such a way that the working pulses PW1 and PW2 are combined to form an odd number of three or more, thereby increasing the output voltage Vswo at the output terminal SWO while improving the efficiency of the power supply.

[0164] Furthermore, in the next cycle, the control unit 400 also turns on the switching element Q1 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, so that the generation of spike noise is minimized, thereby the power supply circuit 10 can minimize the radiated noise emitted toward the outside of the device.

[0165] Furthermore, since radiated noise directed toward the outside of the device is suppressed, the power supply circuit 10 can reduce the cost of suppressing radiated noise.

[0166] Therefore, it can improve power supply efficiency, reduce noise generation, and lower costs.

[0167] In the power supply circuit 10 of this embodiment, the control unit 400 causes the pulse generation unit 200 to generate a working pulse PW2 in such a way that the working pulse PW1 and the working pulse PW2 together make up three pulses.

[0168] During time T1, the control unit 400 repeatedly generates working pulses PW1 and PW2 while the switching elements Q1 and Q2 are stopped.

[0169] In other words, the control unit 400 generates working pulses PW1 and PW2 repeatedly at a frequency F that is one cycle between working pulse PW1 and the next working pulse PW1, or between working pulse PW2 and the next working pulse PW2.

[0170] At this time, since the frequency F of one cycle becomes an audible frequency, audible noise may sometimes be generated from the voltage conversion unit 600, for example.

[0171] The control unit 400 causes the pulse generation unit 200 to generate working pulses PW1 and PW2 in such a way that the number of times the switching elements Q1 and Q2 are turned on / off is the necessary minimum, and causes the pulse generation unit 200 to generate working pulse PW2 in such a way that working pulses PW1 and PW2 are three in total, including working pulse PW1.

[0172] Therefore, the control unit 400 generates operating pulses PW1 and PW2 in such a way that the number of times the switching elements Q1 and Q2 are turned on / off is kept to a necessary minimum, thereby enabling the power supply circuit 10 to suppress the generated audible noise.

[0173] Furthermore, the control unit 400 suppresses audible noise, thereby reducing the cost of suppressing audible noise in the power supply circuit 10.

[0174] Therefore, it can improve power supply efficiency, reduce noise generation, and lower costs.

[0175] In the power supply circuit 10 of this embodiment, the switching elements Q1 and Q2 are FETs. The control unit 400 sets the pulse width Tpw1 of the working pulse PW1 to the pulse generation unit 200 in the following manner: after the last working pulse PW2 is applied to the switching element Q1, which is the high-side FET, the vibration of the switching threshold voltage Vsw or higher between the drain and source of the switching element Q2, which is the low-side FET, remains as the desired level for a period of time T1, which is a predetermined period.

[0176] The pulse generation unit 200 turns the FETs, which are switching elements Q1 and Q2, on / off. As a result, a resonant vibration wave is generated in the output voltage Vswo based on the resonant characteristics set in the resonant circuit unit 500, and a residual vibration voltage is generated.

[0177] Here, the primary coil L1 and capacitor C2 in the resonant circuit section 500 are preset fixed values.

[0178] Therefore, the control unit 400 adjusts the pulse width Tpw1 of the working pulse PW1 based on the information from the output detection unit 800, thereby making the output voltage Vswo remain at a voltage above the switching threshold voltage Vsw during the time T1 period.

[0179] Therefore, during time T1, the pulse generation unit 200 keeps the output voltage Vswo above the switching threshold voltage Vsw, thereby enabling the power supply circuit 10 to minimize the potential difference between the input voltage Vin and the output voltage Vswo in the next cycle.

[0180] Furthermore, by minimizing the generation of spike noise, the power supply circuit 10 can minimize the radiated noise emitted toward the outside of the device.

[0181] Furthermore, by reducing radiated noise directed toward the outside of the device, the power supply circuit 10 can reduce the cost of measures to reduce radiated noise.

[0182] Therefore, it can improve power supply efficiency, reduce noise generation, and lower costs.

[0183] <Second Implementation Method>

[0184] The following uses Figures 4 to 6 The power supply circuit 10A of this embodiment will be described.

[0185] In addition, the power supply IC1A is configured to include a power supply circuit 10A.

[0186] <Structure of a 10A Power Supply Circuit>

[0187] like Figure 4 As shown, the power supply circuit 10A is configured to include an arm section 100, a pulse generation section 200, a voltage detection section 300, a control section 400A, a resonant circuit section 500, a voltage conversion section 600, a rectifier circuit section 700, and an output detection section 800.

[0188] (Regarding the Control Department 400A)

[0189] like Figure 5 As shown, the control unit 400A is connected to the pulse generation unit 200, the voltage detection unit 300, and the output detection unit 800.

[0190] The control unit 400A includes a delay unit 410, a control unit 420A, a counting unit 430, and a timing unit 440.

[0191] The control unit 400A causes the timing unit 440 to time time T5, and triggers the timing unit 440 to time the passage of a certain period of time T6 when the voltage detection unit 300 detects a threshold voltage Vref that exceeds a predetermined threshold. The time T5 is the sum of the time T4 required to count the working pulse PW2 and the shielding time MT.

[0192] The time T6 mentioned here is, for example, a time preset based on the resonance set by the resonant circuit section 500, which is set to the time when the potential difference between the output voltage Vswo and the input voltage Vin is at its minimum.

[0193] Then, after a certain period of time T6, the control unit 400A causes the pulse generation unit 200 to generate working pulses PW1 and PW2 that constitute one cycle, wherein the working pulse PW2 is generated in such a way that it includes at least three working pulses PW1.

[0194] like Figure 5 As shown, the control unit 420A is connected to the pulse generation unit 200, the delay unit 410, the counting unit 430, the timing unit 440, and the output detection unit 800.

[0195] Based on information from the delay unit 410 and the counting unit 430, the control unit 420A controls the switching elements Q1 and Q2 to be turned on / off via the pulse generation unit 200.

[0196] Based on the information about the output voltage Vout sent from the output detection unit 800, which will be described later, the control unit 420A corrects the pulse widths Tpw1 of the working pulse PW1 and Tpw2 of the working pulse PW2.

[0197] Furthermore, based on the information related to the output voltage Vout sent from the output detection unit 800 (described later), the control unit 420A sends information indicating the adjustment of the shielding time MT to the timing unit 440.

[0198] Specifically, the control unit 420A determines, for example, whether the output voltage Vout is higher or lower than a specified threshold based on information from the output detection unit 800.

[0199] When the control unit 420A determines that the output voltage Vout is higher than the specified threshold, the control unit 420A sends information to the timing unit 440 indicating that the shielding time MT is extended.

[0200] In addition, when the control unit 420A determines that the output voltage Vout is lower than the specified threshold, the control unit 420A sends information to the timing unit 440 indicating that the shielding time MT should be shortened.

[0201] The shielding time MT mentioned here is the time during which the working pulses output from the pulse generation unit 200 are stopped, and the counting of the working pulse count in the counting unit 430 is stopped or reset.

[0202] Then, the control unit 420A adjusts the output voltage Vout by sending information indicating the adjustment of the shielding time MT to the timing unit 440.

[0203] The timing unit 440 is connected to the control unit 420A in the control unit 400A.

[0204] The timing unit 440 keeps track of time based on the information indicating the start of timing from the control unit 420A, and outputs information indicating that a predetermined time has elapsed to the control unit 420A.

[0205] Specifically, the timing unit 440, for example, based on information from the control unit 420A, sets the timing start time T3 for generating the working pulse PW1.

[0206] The timing unit 440 times the time T3, which is a period of time with the following time interval: the time interval between the control unit 400A causing the pulse generation unit 200 to output an even number of working pulses PW2 after generating working pulse PW1.

[0207] Then, when the time T3, which is a predetermined time, has elapsed, the timing unit 440 outputs information indicating that time T3 has elapsed to the control unit 420A.

[0208] <Function / Effect>

[0209] use Figure 6 The function and effect of the power supply circuit 10A of this embodiment, configured as described above, will be explained.

[0210] like Figure 6 (a) and Figure 6 As shown in (c), when the control unit 400A obtains information indicating that the output voltage Vswo has become the switching threshold voltage Vsw, it outputs a working pulse PW1 to the switching element Q1 via the pulse generation unit 200.

[0211] Therefore, the switching element Q1 is turned on by the working pulse PW1, and turns off after the output voltage Vswo is output during the pulse width Tpw1 of the working pulse PW1.

[0212] Here, the control unit 400A turns on the switching element Q1 when the potential difference VQ1ds is small, thereby minimizing the spike noise caused by the potential difference.

[0213] Specifically, for example, such as Figure 6 (c) and Figure 6 As shown in (d), the control unit 400A turns on the switching element Q1 at the timing when the delayed signal DS from the delay unit 410 becomes Hi.

[0214] Next, as Figure 6 As shown in (b), the control unit 400A outputs working pulse PW2 to the switching element Q2 via the pulse generation unit 200.

[0215] At this time, the switching element Q2 is turned on by the working pulse PW2, and turns off after the output voltage Vswo becomes GND level during the pulse width Tpw2 of the working pulse PW2.

[0216] Furthermore, such as Figure 6 As shown in (a), the control unit 400A outputs working pulse PW2 to the switching element Q1 via the pulse generation unit 200.

[0217] In this case, the switching element Q1 is turned on by the working pulse PW2, and turns off after outputting the output voltage Vswo during the pulse width Tpw2 of the working pulse PW2.

[0218] As described above, the control unit 400A outputs a working pulse PW1 to the switching element Q1, then outputs a working pulse PW2 to the switching element Q2, and then outputs a working pulse PW2 to the switching element Q1 again. As a result, the output voltage Vswo at the output terminal SWO is increased while improving the efficiency of the power supply.

[0219] Then, the control unit 400A outputs a working pulse PW2 to the high-side switching element Q1 as the last working pulse, thereby ensuring that the output voltage Vswo retains a voltage above the switching threshold voltage Vsw.

[0220] Therefore, the control unit 400A outputs an even number of working pulses PW2.

[0221] Therefore, the control unit 400A generates the working pulse PW2 in an odd number of at least three, including the working pulse PW1.

[0222] like Figure 6 As shown in (e), when the control unit 400A causes the pulse generation unit 200 to generate working pulse PW1, the timing unit 440 causes the time interval between the output of an even number of working pulses PW2 to be counted as a cycle.

[0223] Then, after time T3 has elapsed as a predetermined time, the control unit 400A causes the pulse generation unit 200 to repeat one cycle.

[0224] The timing unit 440 starts timing at the timer that causes the working pulse PW1 to be generated, based on the information from the control unit 400A.

[0225] Specifically, such as Figure 6 (d) and Figure 6 As shown in (e), when the control unit 400A obtains information from the delay unit 410 indicating that the output voltage Vswo has become the switching threshold voltage Vsw, it outputs a working pulse PW1 to the switching element Q1 via the pulse generation unit 200.

[0226] At this time, the control unit 400A causes the timing unit 440 to start timing.

[0227] Then, after the pulse generation unit 200 generates the working pulse PW1, the control unit 400A outputs an even number of working pulses PW2.

[0228] When time T3 has elapsed, the timing unit 440 outputs information indicating that time T3 has elapsed to the control unit 400A.

[0229] After generating working pulse PW1 again based on information from timing unit 440, control unit 400A outputs an even number of working pulses PW2.

[0230] Here, time T3 is a preset time.

[0231] The control unit 400A generates working pulse PW1 based on information from the timing unit 440, and then outputs an even number of working pulses PW2 as a cycle. Every time time T3 elapses, the pulse generation unit 200 repeats this process.

[0232] In addition, such as Figure 6 (f) and Figure 6 As shown in (g), for example, when the control unit 400A generates the working pulse PW2, the control unit 400A causes the timing unit 440 to start timing for times T4 and T5.

[0233] The control unit 400A generates an even number of working pulses PW2 during time T4, and then stops the pulse generation unit 200 during the shielding time MT.

[0234] At this time, the shielding time MT is adjusted by the control unit 420A.

[0235] Specifically, the control unit 420A, for example, determines whether the output voltage Vout is higher or lower than a predetermined threshold based on information from the output detection unit 800, and sends information indicating the adjustment of the shielding time MT to the timing unit 440.

[0236] Then, the control unit 420A adjusts the output voltage Vout by sending information indicating the adjustment of the shielding time MT to the timing unit 440.

[0237] When time T5 has elapsed, the timing unit 440 outputs information indicating that time T5 has elapsed to the control unit 400A.

[0238] The control unit 400A terminates the shielding time MT based on information from the timing unit 440, and starts timing the timing unit 440 for time T6.

[0239] like Figure 6 As shown in (g), when time T6 has elapsed, the timing unit 440 outputs information indicating that time T6 has elapsed to the control unit 400A.

[0240] The control unit 400A, based on information from the timing unit 440, causes the pulse generation unit 200 to generate the working pulse PW1 for the next cycle.

[0241] As described above, in the power supply circuit 10A of this embodiment, the control unit 400A also includes a timing unit 440. The control unit 400A takes the time interval between the pulse generation unit 200 generating a working pulse PW1 and then outputting an even number of working pulses PW2 with a pulse width Tpw1 longer than the working pulse PW1 as a cycle, and makes the timing unit 440 keep time. After a predetermined time T3 has elapsed, the pulse generation unit 200 repeats one cycle.

[0242] That is, the control unit 400A outputs a working pulse PW1 to the switching element Q1 via the pulse generation unit 200 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, based on the information from the delay unit 410.

[0243] At this time, the control unit 400A causes the timing unit 440 to start timing.

[0244] After the pulse generation unit 200 generates the working pulse PW1, the control unit 400A outputs an even number of working pulses PW2.

[0245] Then, after time T3 has elapsed, the timing unit 440 outputs information indicating that time T3 has elapsed to the control unit 400A.

[0246] Based on information from the timing unit 440, the control unit 400A outputs an even number of working pulses PW2 after generating working pulse PW1.

[0247] In other words, the control unit 400A will output an even number of working pulses PW2 after generating working pulse PW1 as a cycle, and the pulse generation unit 200 will repeat every time time T3 elapses.

[0248] Therefore, based on the information from the delay unit 410, the control unit 400A turns on the switching element Q1 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, thereby minimizing the generation of spike noise and thus minimizing the radiated noise emitted toward the outside of the device.

[0249] Next, based on the information from the timing unit 440, the control unit 400A can turn on the switching element Q1 at the timing when the output voltage Vswo in the next cycle becomes the switching threshold voltage Vsw, so as to minimize the generation of spike noise.

[0250] Furthermore, the power supply circuit 10A can minimize the radiated noise emitted towards the outside of the device.

[0251] Furthermore, by reducing radiated noise directed toward the outside of the device, the power supply circuit 10A can reduce the cost of measures to reduce radiated noise.

[0252] Therefore, it can improve power supply efficiency, reduce noise generation, and lower costs.

[0253] In the power supply circuit 10A of this embodiment, the control unit 400A causes the timing unit 440 to time time T5, wherein the time T5 is the sum of the time T4 required for the counting unit 430 to count the working pulse PW2 and the shielding time MT. Furthermore, the control unit 400A is triggered by the voltage detection unit 300 detecting a voltage exceeding a threshold voltage Vref, which is a predetermined threshold, and causes the timing unit 440 to time the passage of a certain period of time T6. After the passage of the certain period of time T6, the pulse generation unit 200 generates working pulses PW1 and PW2 constituting one cycle, wherein the working pulse PW2 is generated in such a way that there are at least three working pulses including working pulse PW1.

[0254] That is, the control unit 400A generates a working pulse PW1 at a timing when the output voltage Vswo becomes the switching threshold voltage Vsw, based on information from the delay unit 410, and then generates an even number of working pulses PW2.

[0255] Next, after time T5 and time T6 have elapsed based on the information from the timing unit 440, the control unit 400A generates working pulse PW1 again, and then outputs an even number of working pulses PW2.

[0256] Therefore, based on the information from the delay unit 410, the control unit 400A turns on the switching element Q1 at the timing when the output voltage Vswo becomes the switching threshold voltage Vsw, thereby minimizing the generation of spike noise and thus minimizing the radiated noise emitted toward the outside of the device.

[0257] Next, based on the information from the timing unit 440, the control unit 400A can turn on the switching element Q1 at the timing when the output voltage Vswo in the next cycle becomes the switching threshold voltage Vsw, so as to minimize the generation of spike noise.

[0258] Furthermore, the power supply circuit 10A can minimize the radiated noise emitted towards the outside of the device.

[0259] Furthermore, by reducing radiated noise directed toward the outside of the device, the power supply circuit 10A can reduce the cost of measures to reduce radiated noise.

[0260] Therefore, it can improve power supply efficiency, reduce noise generation, and lower costs.

[0261] In addition, the control unit 400A can also calculate the time T3, which is a predetermined time, by counting the number of pulses from the delay unit 410, and make the pulse generation unit 200 repeat the cycle of outputting an even number of working pulses PW2 after generating working pulse PW1 at the interval of time T3.

[0262] Alternatively, a processor and a memory can be provided in the power supply circuit 10 and the power supply circuit 10A, and the switching elements Q1 and Q2 can be switched by a program pre-stored in the memory.

[0263] At this time, the processor is configured to include, for example, a pulse generation unit, a control unit, a voltage detection unit, a timing unit, and an output detection unit.

[0264] The arm 100 is located outside the processor and memory, and the processor controls the arm 100 through a program.

[0265] When the processor turns the switching elements Q1 and Q2 on / off, such as Figure 5 As shown, the following situation exists: a loop current RC1 is generated in the closed loop of capacitor C1, which is set at input voltage Vin, and returns to capacitor C1 via arm 100 and GND.

[0266] Furthermore, a loop current RC2 is generated in the closed loop that flows from arm 100 through the resonant circuit section 500 and GND (described later) and back to arm 100.

[0267] The loop currents RC1 and RC2 generate magnetic flux in a direction orthogonal to the current direction, thereby radiating noise toward the outside of the device.

[0268] In addition, the spike noise generated by the alternating switching of switching elements Q1 and Q2 can sometimes lead to radiated noise through the aforementioned closed loop.

[0269] Therefore, by setting up a processor and memory, the circuit structure can be simplified, for example, the size of the closed loop that generates the loop currents RC1 and RC2 can be minimized.

[0270] This reduces radiated noise emitted to the outside of the equipment.

[0271] Furthermore, by storing the processing of the control unit in a computer-readable storage medium, the control unit can read and execute the program stored in the storage medium, thereby enabling the power supply circuit 10 and power supply circuit 10A of the vehicle of the present invention to be implemented.

[0272] The computer system mentioned here includes hardware such as the operating system or peripheral devices.

[0273] Additionally, regarding "computer system," if it utilizes a WWW (World Wide Web) system, it also includes the homepage providing environment (or display environment).

[0274] Alternatively, the program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium.

[0275] Here, the "transmission medium" in the transmission program refers to a medium that has the function of transmitting information, such as a network (communication network) like the Internet or a communication line (communication line) like a telephone line.

[0276] Alternatively, the above program can also be a part of a program used to implement the above functions.

[0277] Alternatively, it could be a so-called differential file (differential program) that can achieve the above functions by combining with programs already stored in the computer system.

[0278] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, as embodiments of the present invention, any power circuit that can be appropriately designed and implemented by those skilled in the art based on the above-described power circuits 10 and 10A, as long as it contains the spirit of the present invention, falls within the technical scope of the present invention.

[0279] Within the scope of the ideas of this invention, any person skilled in the art will be able to conceive of various modifications and alterations, and it can be understood that these modifications and alterations also fall within the technical scope of this invention.

[0280] For example, for the above-described embodiments, as long as they possess the spirit of the present invention, any addition, deletion or design changes to constituent elements, or addition, omission or condition changes to processes made by those skilled in the art are also included within the technical scope of the present invention.

[0281] Furthermore, it is understood that any other effects resulting from the manner described in this embodiment, effects clearly defined according to this specification, or effects that can be reasonably conceived by those skilled in the art are naturally considered effects resulting from this invention.

[0282] Various inventions can be formed by appropriate combinations of the various constituent elements disclosed in the above embodiments.

[0283] For example, several constituent elements may be deleted from all the constituent elements shown in the implementation.

[0284] Furthermore, the constituent elements of different implementation methods can be appropriately combined.

Claims

1. A power supply IC and power supply circuit in the form of a resonant converter, which controls multiple switching elements, characterized in that, The power IC and power circuit include: A pulse generation unit generates working pulses that turn the switching element on / off. A voltage detection unit detects the output voltage of the switching element; and The control unit controls the pulse generation unit based on the voltage level detected by the voltage detection unit. The control unit, based on the voltage level detected by the voltage detection unit, causes the pulse generation unit to generate a first working pulse having a first pulse width. Then, the pulse generation unit generates a second working pulse with a pulse width longer than the pulse width of the first working pulse, in an odd number of pulses including the first working pulse (at least three).

2. The power supply IC and power supply circuit according to claim 1, characterized in that, For the first working pulse and the second working pulse whose pulse width is longer than that of the first working pulse, the controlling unit causes the pulse generating unit to generate the second working pulse in such a way that there are three pulses, including the first working pulse.

3. The power supply IC and power supply circuit according to claim 1 or 2, characterized in that, The switching element is a FET. The controlling unit causes the pulse generating unit to set the first pulse width of the first operating pulse in such a way that, after the last second operating pulse is applied to the FET on the high side, a desired level of vibration remains between the drain and source of the FET on the low side for a specified period.

4. The power supply IC and power supply circuit according to claim 3, characterized in that, The control unit also includes a timing unit. The control unit will cause the pulse generation unit to output an even number of second working pulses with a pulse width longer than the pulse width of the first working pulse after generating the first working pulse, and the timing unit will keep time. After a predetermined time has elapsed, the pulse generation unit will repeat the execution of the one cycle.

5. The power supply IC and power supply circuit according to claim 4, characterized in that, The control unit causes the timing unit to time the time required to include the shielding period in counting the second working pulse, and triggers the timing unit to time the elapsed time of a certain period when the voltage detection unit detects a voltage exceeding a predetermined threshold. After the certain period of delay has elapsed, the pulse generation unit generates the first working pulse and the second working pulse constituting one cycle, wherein the second working pulse is generated in such a way that there are at least three pulses, including the first working pulse.

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