Ultrathin audio power amplifier power supply
By adopting interlaced PFC circuits in audio amplifier power supplies, the problem of high current and voltage stress in traditional PFC circuits in high power applications is solved, and better thermal performance and smaller current ripple are achieved, suitable for thin applications.
Patent Information
- Application Number
- CN202420487491.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-13
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-03-13
AI Technical Summary
Traditional single-weight Boost PFC circuits have problems with high current and voltage stress in high power applications, resulting in severe radiation and conductive EMI and large inductor volume.
Using an interleaved PFC circuit, the first and second PFC branches connected in parallel include inductors and diodes, respectively, and the PFC master driver signal is applied between the inductors and diodes through the switching circuit to achieve interleaved operation.
Interleaved PFC supports the use of smaller components, improves thermal performance, increases power range, and reduces current ripple, making it suitable for thin applications with strict form factor requirements.
Smart Images
Figure CN222620895U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of audio, in particular to an ultra-thin audio power amplifier power supply. Background Art
[0002] In recent years, PFC circuits (power factor correction circuits) have been frequently used in some applications where the power factor of the power supply is strictly required in the audio power amplifier industry. The common practice in the industry now is: either not to use PFC, which will lead to poor grid quality; or to use a common single-channel CCM mode PFC structure. The use of the traditional single-boost PFC structure is limited. When the power increases, the switching devices of the single-boost PFC must withstand greater current and voltage stress. During the switching process, excessive dv / dt and di / dt appear at key nodes in the circuit, which will cause serious radiation and conducted EMI. In addition, the PFC inductor and switch tube current are large, and the inductor volume is large. Summary of the invention
[0003] The technical problem to be solved by the utility model is to provide an ultra-thin audio power amplifier power supply, which is conducive to slim design.
[0004] In order to solve the above technical problems, the technical solution of the utility model is: an ultra-thin audio power amplifier power supply, comprising a power supply circuit, the power supply circuit comprising an AC power input terminal, a PFC boost converter and a voltage output terminal; the PFC boost converter comprises a PFC controller and a PFC circuit, the PFC circuit comprises a first PFC branch and a second PFC branch connected in parallel, the first PFC branch comprises an inductor L1 and a diode D1, the input terminal of the inductor L1 is connected to the AC power input terminal, the output terminal of the inductor L1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the voltage output terminal, and the PFC master controller drive signal S1 is applied between the inductor L1 and the diode D1 through a first switch circuit; the second PFC branch comprises an inductor L2 and a diode D2, the input terminal of the inductor L2 is connected to the AC power input terminal, the output terminal of the inductor L2 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the voltage output terminal, and the PFC master controller drive signal S2 is applied between the inductor L2 and the diode D2 through a second switch circuit. Principle of the utility model: Interleaved PFC supports the use of smaller components, can improve thermal performance, increase power range and reduce current ripple, which is very suitable for slim applications with extremely strict requirements on form factor, such as the latest ultra-thin 1U digital amplifiers.
[0005] As an improvement, the signal at the AC power input end is output to the voltage output end after passing through a filtering surge protection relay, a rectifier bridge, a PFC boost converter and a full-bridge soft switching converter in sequence.
[0006] As an improvement, the model of the PFC master controller is UCC28070A, and its pin 17 generates a driving signal S1, and its pin 14 generates a driving signal S2.
[0007] As an improvement, the drive signals S1 and S2 operate alternately with a phase shift of 180°.
[0008] As an improvement, the first switch circuit includes a MOS tube M1 and a transformer T1, the gate of the MOS tube M1 receives a driving signal S1, the drain of the MOS tube M1 is connected to one end of the main coil of the transformer T1, and the other end of the main coil of the transformer T1 is connected between the inductor L1 and the diode D1; the second switch circuit includes a MOS tube M2 and a transformer T2, the gate of the MOS tube M2 receives a driving signal S2, the drain of the MOS tube M2 is connected to one end of the main coil of the transformer T2, and the other end of the main coil of the transformer T2 is connected between the inductor L2 and the diode D2.
[0009] Compared with the prior art, the utility model has the following beneficial effects:
[0010] Interleaved PFC enables the use of smaller components, improves thermal performance, increases power range and reduces current ripple, making it ideal for slim applications where form factor requirements are extremely stringent. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is a circuit block diagram of the utility model.
[0012] Figure 2 Simplified circuit diagram for a PFC boost converter.
[0013] Figure 3 This is the circuit diagram of the filter surge protection relay.
[0014] Figure 4 This is the practical application circuit diagram of the PFC boost converter.
[0015] Figure 5 This is the circuit diagram of the PFC controller.
[0016] Figure 6 Input voltage and input current waveform.
[0017] Figure 7 This is the waveform diagram of the mutual cancellation of inductor ripple current. DETAILED DESCRIPTION
[0018] The utility model will be further described below in conjunction with the accompanying drawings.
[0019] like Figures 1 to 5As shown, an ultra-thin audio power amplifier power supply includes a power supply circuit, which includes an AC power input terminal, a PFC boost converter and a voltage output terminal; the signal at the AC power input terminal is sequentially output to the voltage output terminal after passing through a filtering anti-surge relay, a rectifier bridge, a PFC boost converter and a full-bridge soft switching converter.
[0020] like Figure 2 As shown, the PFC boost converter includes a PFC controller and a PFC circuit. The PFC circuit includes a first PFC branch and a second PFC branch connected in parallel, the first PFC branch includes an inductor L1 and a diode D1, the input end of the inductor L1 is connected to the AC power input end, the output end of the inductor L1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the voltage output end, and the PFC master controller drive signal S1 is applied between the inductor L1 and the diode D1 through the first switch circuit; the second PFC branch includes an inductor L2 and a diode D2, the input end of the inductor L2 is connected to the AC power input end, the output end of the inductor L2 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the voltage output end, and the PFC master controller drive signal S2 is applied between the inductor L2 and the diode D2 through the second switch circuit.
[0021] like Figure 2 As shown, the model of the PFC master controller is UCC28070A. The interleaved PFC circuit composed of a single-chip UCC28070A supports kilowatt-level power systems, helps to reduce total harmonic distortion when lightly loaded, uses phase management function to improve load efficiency, and compared with traditional single-phase, the interleaving type can reduce input and output current ripples and improve thermal management levels through electromagnetic distribution. The typical application circuit of UCC28070A, pin 1 is connected to a capacitor to set the frequency jitter rate, pin 2 is connected to a resistor to set the jitter amplitude, pin 3 is the voltage error amplifier output, pin 4 is the output voltage detection, pin 5 is the line voltage input, pin 6 is the multiplier current output, connect the resistor to GND to set the gain of the multiplier, pin 7 is an external resistor to set the amplitude of the current synthesis down ramp, pins 8 and 9 are current detection inputs, pin 10 is the peak current limit terminal, pins 11 and 12 are the reference voltage for the current amplifier output pin, pins 14 and 17 are the drive output terminals, pins 15 and 16 are the positive and ground for the chip power supply respectively, pin 18 is the soft start and external fault interface, pin 19 is the frequency setting terminal, and pin 20 is the maximum duty cycle setting terminal. When powered on, the auxiliary power supply provides a 13VP voltage to the p15_VCC pin, and pins 14 and 17 output drive signals with a phase difference of 180 degrees, and pin 4 detects the output voltage VSENSE. Figure 5 As shown in the figure, the input voltage and input current waveforms are measured during operation. From the waveforms, it can be seen that the voltage and current waveforms of the mains are synchronized and are both sinusoidal. Figure 6As shown in the figure, since the ripple currents of the input inductors can cancel each other out, the input ripple current is reduced.
[0022] Compared with single-phase PFC of the same power, the significant reduction in input current ripple makes it easier to handle conducted EMI, reducing the size of the EMI filter. In addition, due to the reduction of high-frequency ripple current on the output capacitor, the output capacitance is reduced, further reducing the average current of each phase and the size of the ripple boost inductor is also much smaller than that of a single phase. UCC28070A has a unique current synthesis technology that eliminates the diode sampling circuit and frequency jitter technology.
[0023] Interleaved PFC enables the use of smaller components, improves thermal performance, increases power range and reduces current ripple, making it ideal for slim applications with extremely stringent form factor requirements, such as the latest ultra-slim 1U digital amplifiers.
Claims
1. An ultra-thin audio power amplifier power supply, including a power supply circuit, characterized in that: The power supply circuit includes an AC power input terminal, a PFC boost converter and a voltage output terminal; the PFC boost converter includes a PFC controller and a PFC circuit, the PFC circuit includes a first PFC branch and a second PFC branch connected in parallel, the first PFC branch includes an inductor L1 and a diode D1, the input terminal of the inductor L1 is connected to the AC power input terminal, the output terminal of the inductor L1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the voltage output terminal, and the PFC master controller drive signal S1 is applied between the inductor L1 and the diode D1 through a first switch circuit; the second PFC branch includes an inductor L2 and a diode D2, the input terminal of the inductor L2 is connected to the AC power input terminal, the output terminal of the inductor L2 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the voltage output terminal, and the PFC master controller drive signal S2 is applied between the inductor L2 and the diode D2 through a second switch circuit.
2. The ultra-thin audio power amplifier power supply according to claim 1, characterized in that: The signal at the AC power input end is output to the voltage output end after passing through a filtering surge protection relay, a rectifier bridge, a PFC boost converter and a full-bridge soft switching converter in sequence.
3. The ultra-thin audio power amplifier power supply according to claim 1, characterized in that: The model of the PFC master controller is UCC28070A, and its pin 17 generates a driving signal S1, and its pin 14 generates a driving signal S2.
4. The ultra-thin audio power amplifier power supply according to claim 1, characterized in that: The drive signals S1 and S2 operate alternately with a phase shift of 180°.
5. The ultra-thin audio power amplifier power supply according to claim 1, characterized in that: The first switch circuit includes a MOS tube M1 and a transformer T1, wherein the gate of the MOS tube M1 receives a driving signal S1, the drain of the MOS tube M1 is connected to one end of the main coil of the transformer T1, and the other end of the main coil of the transformer T1 is connected between the inductor L1 and the diode D1; the second switch circuit includes a MOS tube M2 and a transformer T2, wherein the gate of the MOS tube M2 receives a driving signal S2, the drain of the MOS tube M2 is connected to one end of the main coil of the transformer T2, and the other end of the main coil of the transformer T2 is connected between the inductor L2 and the diode D2.