Small-size high-precision ac-dc power supply module

Abstract

The utility model discloses a small volume high accuracy ACDC power module, include: the main control module, drive module, dynamic regulation module and power output module that are connected, wherein, the input of main control module is connected external voltage source through filter module, and drive module includes the switching drive unit and overcurrent protection unit that are connected, and switching drive unit is connected with the output of main control module, and overcurrent protection unit is connected with power output module, power output module connects rear end load, and dynamic regulation module is connected with main control module, is used to dynamic regulation power output module, to the rear end load output stable voltage, through above -mentioned design solves the technical problem that the existing AC -DC power module volume is big, installs to the PCB circuit board and exists the big area of board, the big output ripple.

Description

Technical Field

[0001] This utility model relates to the field of power module conversion circuit technology, specifically to a small-volume, high-precision ACDC power module. Background Technology

[0002] Traditional AC-DC power modules are bulky, resulting in a large footprint and high output ripple when mounted on a PCB.

[0003] Furthermore, traditional AC-DC power modules often use PSR (primary-side feedback) to control the output voltage in order to reduce costs. The output voltage accuracy can only reach about 5%, and the output voltage requires a minimum load, resulting in low conversion efficiency of the power module.

[0004] To address this issue, our company offers a compact, high-precision AC / DC power module. Utility Model Content

[0005] The purpose of this invention is to overcome the defects in the prior art and provide a small-volume, high-precision AC / DC power module.

[0006] To achieve the above objectives, this utility model adopts the following technical solution:

[0007] A small-volume, high-precision AC-DC power module, characterized in that:

[0008] This includes the interconnected main control module, drive module, dynamic adjustment module, and power output module;

[0009] The input terminal of the main control module is connected to an external voltage source through a filter module. The drive module includes a connected switch drive unit and an overcurrent protection unit. The switch drive unit is connected to the output terminal of the main control module, and the overcurrent protection unit is connected to the power output module.

[0010] The power output module is connected to the downstream load, and the dynamic adjustment module is connected to the main control module to dynamically adjust the power output module to output a stable voltage to the downstream load.

[0011] Preferably, it also includes a filtering module, which includes a patch bridge rectifier for performing full-bridge rectification on the input AC signal to form a pulsating DC waveform signal;

[0012] The input terminal of the surface mount bridge rectifier is connected to an external voltage source through an LC filter unit, and the output terminal of the surface mount bridge rectifier is connected to the driver module through a sixth capacitor.

[0013] Preferably, the main control module includes an AC-DC control chip. The fifth pin of the AC-DC control chip is connected to the output terminal of the filter module through a series-connected start-up resistor to obtain the start-up current. The fifth pin of the AC-DC control chip is also connected to a CRC filter unit. The CRC filter unit consists of a first resistor, a first capacitor, and a twenty-seventh capacitor. The first resistor is connected to the switch drive module through an eleventh diode to output the working voltage to the switch drive module. The other ends of the first capacitor and the twenty-seventh capacitor are grounded.

[0014] Preferably, the switch driving unit includes a first switching transistor, wherein a second resistor and a first diode connected in parallel to the first terminal of the first switching transistor are connected at one end, and the other end of the second resistor and the first diode connected in parallel is connected to the sixth pin of the AC-DC control chip of the chip driving module.

[0015] The second terminal of the first switching transistor is connected to the overcurrent protection unit and the power output module;

[0016] The third terminal of the first switching transistor is connected to the fourth pin of the AC-DC control chip and to the power output module through the parallel 34th and 35th resistors. The other end of the 34th and 35th resistors is also connected to the first terminal of the first switching transistor through the 36th resistor.

[0017] Preferably, the first switching transistor is an NMOS transistor, the gate of which is connected to the anode of the first diode, its source is connected to the overcurrent protection unit and the power output module, and its drain is connected to the thirty-fourth resistor, the thirty-fifth resistor and the AC-DC control chip.

[0018] Preferably, the overcurrent protection unit includes an RCD absorption circuit consisting of a 24th capacitor, a 30th resistor, and a 12th diode, wherein the anode of the 12th diode is connected to the second terminal of the first switching transistor, and the other terminals of the 24th capacitor and the 30th resistor are connected to the power output module.

[0019] Preferably, the power output module includes a transformer. The first pin of the transformer is connected to the main control module. The second pin of the transformer is grounded to the 34th, 35th, and 36th resistors respectively. The third pin of the transformer is connected to the gate of the first switching transistor. The fourth pin of the transformer is connected to the fifth pin through the 28th capacitor. The eighth pin of the transformer is connected to an RC snubber unit and a 10th diode connected in parallel. A CLC filter unit is also connected between the RC snubber unit, the 10th diode, and the fifth pin of the transformer. The CLC filter unit is connected to the output contacts for connecting the load.

[0020] Preferably, the dynamic adjustment module includes an optocoupler. The third and fourth pins of the optocoupler are connected to the main control module. The first pin of the optocoupler is connected to the output voltage ISO_+12V through an eighth resistor. A ninth resistor is connected between the first and second pins of the optocoupler. The ninth resistor is connected to the second pin of the third voltage reference source. The first and second pins of the third voltage reference source are connected through a fifth capacitor. The fifth capacitor is also connected to a tenth and an eleventh resistor in parallel. The tenth resistor is connected to the output voltage ISO_+12V, and the eleventh resistor is connected to the output voltage ISO_GND.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] The AC signal first undergoes full-bridge rectification via the ninth surface-mount bridge rectifier D9, resulting in a pulsating DC waveform. It then passes through the chip driver module to obtain the starting current, followed by the switch driver unit and overcurrent protection unit. The RCD absorption module of the overcurrent protection unit absorbs and blocks turn-off spikes to reduce overall circuit radiation. Finally, the output module completes the power current conversion process. It also uses an AC-DC control chip U1 (CR6863B) + optocoupler feedback voltage scheme, achieving an output voltage accuracy within 2%. Furthermore, there is no minimum load requirement for the output voltage. The overall circuit features low output ripple and a small footprint. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the filter module structure of this utility model;

[0025] Figure 3 This is a schematic diagram of the main control module structure of this utility model;

[0026] Figure 4 This is a schematic diagram of the switch drive unit structure of this utility model;

[0027] Figure 5 This is a schematic diagram of the power output module structure of this utility model;

[0028] Figure 6 This is a schematic diagram of the dynamic adjustment module structure of this utility model. Detailed Implementation

[0029] A preferred embodiment of the present invention will now be described in conjunction with the accompanying drawings, providing a clear and complete description of the technical solution in this preferred embodiment.

[0030] A small-volume, high-precision AC-DC power module includes: a main control module, a drive module, a dynamic adjustment module, and a power output module connected to each other; wherein, the input terminal of the main control module is connected to an external voltage source through a filter module, and the drive module includes a switch drive unit and an overcurrent protection unit connected to each other, the switch drive unit is connected to the output terminal of the main control module, and the overcurrent protection unit is connected to the power output module.

[0031] The power output module is connected to the downstream load, and the dynamic adjustment module is connected to the main control module to dynamically adjust the power output module to output a stable voltage to the downstream load.

[0032] like Figure 1 As shown: Through the above design, the AC signal first undergoes full-bridge rectification through the ninth surface-mount bridge rectifier D9, which is rectified into a pulsating DC waveform. Then, it passes through the chip driver module to obtain the starting current, and then through the switch driver unit and the overcurrent protection unit. The RCD absorption module of the overcurrent protection unit absorbs the turn-off spikes to reduce the overall circuit's external radiation. Finally, the power current conversion process is completed through the output module.

[0033] It also uses an AC-DC control chip U1 (CR6863B) + optocoupler feedback voltage solution, achieving an output voltage accuracy of within 2%, and there is no minimum load requirement for the output voltage. The overall power module conversion efficiency is higher than traditional solutions, making it more environmentally friendly and energy-saving.

[0034] Specifically, it also includes a filtering module, which includes a ninth surface-mount bridge rectifier D9. The ninth surface-mount bridge rectifier D9 is used to perform full-bridge rectification on the input AC signal to form a pulsating DC waveform signal. The input terminal of the ninth surface-mount bridge rectifier D9 is connected to an external voltage source through an LC filter unit, and the output terminal of the ninth surface-mount bridge rectifier D9 is connected to the drive module through a sixth capacitor C6.

[0035] like Figure 2As shown: Through the above design, the electric contact TP3 and the electric contact TP4 are connected to the external 220VAC input. After passing through the fourth inductor L4 and the seventh CBB capacitor C7, an LC filter is formed to filter out high-frequency interference and surge spikes. The fourth inductor L4 and the seventh CBB capacitor C7 improve the anti-interference ability of the entire filter module under group pulses and surge impacts, and improve the EMS performance of the power supply module. For a signal with a frequency of f, the impedance generated by the fourth inductor L4 is XL = 2πfL, and the impedance generated by the seventh capacitor C7 is XC = 1 / (2πfC). For a high-frequency signal with a frequency of f and a peak-to-peak value of V, after being filtered by the fourth inductor L4 and the seventh CBB capacitor C7, the voltage is divided into V / (4π2f2LC + 1) < V, so the peak value of the high-frequency signal is reduced. The AC signal is full-wave rectified by the ninth patch bridge rectifier D9 into a pulsating DC waveform. The pulsating DC waveform becomes a DC waveform with very small fluctuations through the peak clipping and valley filling effect of the sixth capacitor C6, completing the filtering effect on the DC H_VCC.

[0036] Specifically, the main control module includes an AC-DC control chip. The fifth pin of the AC-DC control chip is connected to the output end of the filter module through a series-connected startup resistor to obtain the startup current. The fifth pin of the AC-DC control chip is also connected to a CRC filter unit, which is composed of the first resistor R1, the first capacitor C1, and the twenty-seventh capacitor C27. The first resistor R1 is connected to the switch drive module through the eleventh diode D11 to supply the working voltage to the switch drive module. The other ends of the first capacitor C1 and the twenty-seventh capacitor C27 are grounded.

[0037] As Figure 3 Shown: Through the above design, the IST current consumed by the AC-DC control chip U1 at the beginning of startup is in the μA level. Therefore, the startup current is obtained from H_VCC in a resistor current limiting mode through the startup sixth resistor R6 and the seventh resistor R7. When the charging current is greater than the consumption current IST of U1 at the beginning stage, the startup current charges the twenty-seventh capacitor C27, the first resistor R1, and the first capacitor C1. Therefore, when the VDD voltage slowly rises to the UVLOOFF voltage, U1 starts through the electric energy stored in the twenty-seventh capacitor C27 and the first capacitor C1. U1 controls the switch of the MOS transistor Q1. The waveform generated by the auxiliary winding 1, 2 of the transformer T1 is rectified by the eleventh diode D11, and after being filtered by the CRC composed of the first capacitor C1, the first resistor R1, and the twenty-seventh capacitor C27, it provides a larger supply current to U1, meeting the current consumption during the normal switching operation of U1. The entire AC-DC completes the process from startup to the normal switching output of the working voltage ISO_+12V.

[0038] Specifically, the switch driving unit includes a first switch transistor Q1, wherein a second resistor R2 connected in parallel with the first terminal of the first switch transistor Q1 and a first diode D1 are connected at one end, and the other end of the second resistor R2 connected in parallel and the first diode D1 are connected to the sixth pin of the AC-DC control chip of the chip driving module.

[0039] The second terminal of the first switching transistor Q1 is connected to the overcurrent protection unit and the power output module;

[0040] The third terminal of the first switching transistor Q1 is connected to the fourth pin of the AC-DC control chip and to the power output module through the parallel 34th resistor R34 and 35th resistor R35. The other end of the 34th resistor R34 and 35th resistor R35 is also connected to the first terminal of the first switching transistor Q1 through the 36th resistor R36.

[0041] The first switching transistor Q1 is an NMOS transistor. The gate of the NMOS transistor is connected to the anode of the first diode D1, its source is connected to the overcurrent protection unit and the power output module, and its drain is connected to the thirty-fourth resistor R34, the thirty-fifth resistor R35 and the AC-DC control chip.

[0042] The overcurrent protection unit includes an RCD absorption circuit consisting of a 24th capacitor C24, a 30th resistor R30, and a 12th diode D12. The anode of the 12th diode D12 is connected to the second terminal of the first switching transistor, and the other terminals of the 24th capacitor and the 30th resistor are connected to the power output module and the filter module, respectively.

[0043] like Figure 4 As shown: Through the above design, when U1 starts the switch, a PWM waveform is output through the GATE pin. When the PWM waveform is high, the MOSFET Q1 is turned on through the second resistor R2. By adjusting the value of the second resistor R2, the dv / dt of Q1's conduction can be adjusted, reducing the problem of excessive dv / dt and strong outward radiation caused by Q1's rapid conduction. When the PWM waveform outputs a low level, Q1 needs to be turned off quickly, so D1 is turned on. The gate electrons of Q1 are quickly discharged through D1, achieving the purpose of quickly turning off Q1.

[0044] The 36th resistor R36, connected in parallel between the gate (G) and source (S) terminals of Q1, acts as a default turn-off for Q1, preventing an abnormal floating high level at the gate of Q1 when the gate is floating before the operating voltage of U1 is reached. R34 and R35, connected in series with the source (S) terminal of Q1, sample the current flowing between the drain (D) and source (S) terminals of Q1. When Q1 is turned on, the CS signal will induce a spike due to the high dv / di generated during conduction. U1 internally performs a delay sampling of the CS signal to avoid this spike.

[0045] After Q1 is turned on, due to the inductive effect of T1, the current flowing through Q1 gradually increases, resulting in a rising current signal on CS. When Q1 is turned off, the CS signal drops to 0. When the power module output is overloaded or short-circuited, the slope of the CS signal is much greater than the normal operating slope. U1 detects overcurrent or overload conditions by judging the CS signal and uses a hiccup mode to detect whether the abnormal state has ended. Resistors R34 and R35 are connected in parallel to improve system reliability and overload capacity.

[0046] When Q1 is turned off, a very high voltage turn-off spike will be generated at pin 3 due to the leakage inductance of transformer T1. This turn-off spike, besides generating high levels of external radiation, can also cause Q1 to break down and damage the entire power supply module because the voltage exceeds Q1's VDS. This high voltage spike is absorbed by capacitor C24 after passing through diode D12 (the twelfth diode), preventing the generation of a high spike. After absorbing the spike, resistor R30 discharges capacitor C24, preventing it from becoming too overvoltaged and unable to absorb the next spike.

[0047] When Q1 is turned on, the upper end of the twelfth diode D12 is at a high level and the lower end is at a low level, thus the twelfth diode D12 is turned off. The RCD snubber circuit, composed of the twenty-fourth capacitor C24, the thirtieth resistor R30, and the twelfth diode D12, serves to absorb only the turn-off spikes.

[0048] Specifically, the power output module includes a transformer T1. The first pin of the transformer T1 is connected to the main control module. The second pin of the transformer T1 is grounded to the 34th resistor R34, the 35th resistor R35, and the 36th resistor R36, respectively. The third pin of the transformer T1 is connected to the gate of the first switching transistor Q1. The fourth pin of the transformer T1 is connected to the fifth pin through the 28th capacitor C28. The eighth pin of the transformer T1 is connected to an RC snubber unit and a 10th diode connected in parallel. A CLC filter unit is also connected between the RC snubber unit, the 10th diode D10, and the fifth pin of the transformer T1. The CLC filter unit is connected to the output contacts used for connecting the load.

[0049] like Figure 5 As shown: Through the above design, when the MOSFET Q1 is turned on, the primary coil of the transformer T1 is turned on to store energy. Pin 5 of the secondary winding of transformer T1 is at a high level, pin 8 is at a low level, and the tenth rectifier diode D10 is turned off.

[0050] When MOSFET Q1 is turned off, pin 3 of the primary winding of transformer T1 is high and pin 4 is low. Pin 8, which is the same terminal, is also high and pin 5 is low. At this time, the tenth rectifier diode D10 is turned on. After the tenth rectifier diode D10 is turned on, the secondary winding of transformer T1 charges the fourth capacitor C4. The fourth capacitor C4, the first inductor L1, and the twenty-sixth capacitor C26 form a CLC filter circuit, which further reduces the ripple of the output voltage ISO_+12V. The RC snubber circuit composed of the fourth resistor R4 and the third capacitor C3 absorbs the reverse spike on the tenth rectifier diode D10, reducing the radiation of the high-frequency rectifier circuit. When the module supplies power externally, ISO_+12V flows back to ISO_GND through the load, and then through the secondary windings 5 ​​and 8 of transformer T1, forming a complete current loop through the tenth rectifier diode D10 and the first inductor L1.

[0051] Specifically, the dynamic adjustment module includes an optocoupler OP1. The third and fourth pins of the optocoupler OP1 are connected to the main control module. The first pin of the optocoupler OP1 is connected to the output voltage ISO_+12V through the eighth resistor R8. A ninth resistor R9 is connected between the first and second pins of the optocoupler OP1. The ninth resistor R9 is connected to the second pin of the third voltage reference source. The first and second pins of the third voltage reference source are connected through the fifth capacitor C5. The fifth capacitor C5 is also connected to the tenth resistor R10 and the eleventh resistor R11 in parallel. The tenth resistor R10 is connected to the output voltage ISO_+12V, and the eleventh resistor R11 is connected to the output voltage ISO_GND.

[0052] like Figure 6 As shown: Through the above design, the output voltage ISO_+12V is divided by the tenth resistor R10 and the eleventh resistor R11 and then enters the REF terminal of pin 1 of the voltage reference source U3.

[0053] When the voltage divider voltage [ISO_+12V*R11 / (R10+R11)] of the tenth resistor R10 and the eleventh resistor R11 is greater than 2.5V, the output impedance of pins 2 and 3 of the voltage reference source U3 decreases. The current through the eighth resistor R8 and the internal infrared LED of the optocoupler OP1 increases, resulting in more photons emitted by the infrared LED to the internal phototransistor, and thus increasing the IC current of the phototransistor. The current from pin FB of the AC-DC control chip U1 to pin GND increases, and the voltage at pin FB decreases. The AC-DC control chip U1 reduces the conduction time of MOSFET Q1, thereby reducing the conduction time of the primary coil of transformer T1 and lowering the secondary output voltage ISO_+12V.

[0054] When [ISO_+12V*R11 / (R10+R11)]<2.5V, the output impedance of pins 2 and 3 of the voltage reference source U3 increases, the current of the internal infrared LED of OP1 decreases, the current of the phototransistor IC of OP1 decreases, and the current from pin FB to pin GND of the AC-DC control chip U1 decreases. The AC-DC control chip U1 increases the conduction time of MOSFET Q1, and the ISO_+12V voltage increases, thereby achieving a dynamic output stability of ISO_+12V at [(R10+R11)*R11*2.5]V. C5 connected between pins 1 and 2 of the voltage reference source U3 accelerates the feedback speed of the voltage reference source U3. The ninth resistor R9 connected in parallel with the infrared LED of OP1 provides the minimum operating current of 1mA required by the voltage reference source U3.

[0055] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A small-volume, high-precision AC / DC power module, characterized in that: This includes the interconnected main control module, drive module, dynamic adjustment module, and power output module; The input terminal of the main control module is connected to an external voltage source through a filter module. The drive module includes a connected switch drive unit and an overcurrent protection unit. The switch drive unit is connected to the output terminal of the main control module, and the overcurrent protection unit is connected to the power output module. The power output module is connected to the back-end load, and the dynamic adjustment module is connected to the main control module to dynamically adjust the power output module to output a stable voltage to the back-end load.

2. The small-volume, high-precision ACDC power module according to claim 1, characterized in that: It also includes a filtering module, which includes a patch bridge rectifier used to perform full-bridge rectification on the input AC signal to form a pulsating DC waveform signal; The input terminal of the surface mount bridge rectifier is connected to an external voltage source through an LC filter unit, and the output terminal of the surface mount bridge rectifier is connected to the drive module through a sixth capacitor.

3. The small-volume, high-precision ACDC power module according to claim 2, characterized in that: The main control module includes an AC-DC control chip. The fifth pin of the AC-DC control chip is connected to the output terminal of the filter module through a series-connected start-up resistor to obtain the start-up current. The fifth pin of the AC-DC control chip is also connected to a CRC filter unit. The CRC filter unit consists of a first resistor, a first capacitor, and a twenty-seventh capacitor. The first resistor is connected to the switch drive unit through an eleventh diode to output the working voltage to the switch drive unit. The other ends of the first capacitor and the twenty-seventh capacitor are grounded.

4. The small-volume, high-precision ACDC power module according to claim 3, characterized in that: The switch driving unit includes a first switching transistor, wherein a second resistor and a first diode connected in parallel to the first terminal of the first switching transistor are connected at one end, and the other end of the second resistor and the first diode connected in parallel is connected to the sixth pin of the AC-DC control chip of the chip driving module. The second terminal of the first switching transistor is connected to the overcurrent protection unit and the power output module; The third terminal of the first switching transistor is connected to the fourth pin of the AC-DC control chip and to the power output module through the thirty-fourth and thirty-fifth resistors in parallel. The other ends of the thirty-fourth and thirty-fifth resistors are also connected to the first terminal of the first switching transistor through the thirty-sixth resistor.

5. The small-volume, high-precision ACDC power module according to claim 4, characterized in that: The first switching transistor is an NMOS transistor. The gate of the NMOS transistor is connected to the anode of the first diode, its source is connected to the overcurrent protection unit and the power output module, and its drain is connected to the thirty-fourth resistor, the thirty-fifth resistor and the AC-DC control chip.

6. The small-volume, high-precision ACDC power module according to claim 5, characterized in that: The overcurrent protection unit includes an RCD absorption circuit consisting of a 24th capacitor, a 30th resistor, and a 12th diode. The anode of the 12th diode is connected to the second terminal of the first switching transistor, and the other terminals of the 24th capacitor and the 30th resistor are connected to the power output module.

7. The small-volume, high-precision ACDC power module according to claim 4, characterized in that: The power output module includes a transformer. The first pin of the transformer is connected to the main control module. The second pin of the transformer is grounded to the 34th, 35th, and 36th resistors, respectively. The third pin of the transformer is connected to the gate of the first switching transistor. The fourth pin of the transformer is connected to the fifth pin through the 28th capacitor. The eighth pin of the transformer is connected to an RC snubber unit and a 10th diode connected in parallel. A CLC filter unit is also connected between the RC snubber unit, the 10th diode, and the fifth pin of the transformer. The CLC filter unit is connected to the output contacts for connecting the load.

8. The small-volume, high-precision ACDC power module according to claim 7, characterized in that: The dynamic adjustment module includes an optocoupler. The third and fourth pins of the optocoupler are connected to the main control module. The first pin of the optocoupler is connected to the output voltage ISO_+12V through an eighth resistor. A ninth resistor is connected between the first and second pins of the optocoupler. The ninth resistor is connected to the second pin of the third voltage reference source. The first and second pins of the third voltage reference source are connected through a fifth capacitor. The fifth capacitor is also connected to a tenth and an eleventh resistor in parallel. The tenth resistor is connected to the output voltage ISO_+12V, and the eleventh resistor is connected to the output voltage ISO_GND.

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