Preface
The charging head network got a liquid crystal display power board launched by DOZWATT Dongzhun Power Supply, this power board model is ZW9300-A, supports 100-240Vac wide voltage input, output voltage has 5V standby output, 5V, 12V and 19V output, and LED backlight output.
The power board has 19V4A and 12V5A outputs, which can meet the power supply of all-in-one computers and other equipment. Among them, the output voltage of the LED backlight is 80-240V, the output power is 150W, and the total output power of the power board is 300W, which is suitable for 60-65 inch screens. The measured size of this power board is 285*180*17.6mm. Let's bring the dismantling of this power board, let's take a look at the scheme and materials.
Appearance of the ZW9300-A power board
The power board of Dongzhun Electronics is ultra-thin, and most of the components are horizontal.
The back of the power strip is insulated with barley paper.
The corresponding power devices of the power board are provided with heat sinks.
An insulated Mylar sheet is provided on the back of the power strip.
Mylar sheets are supported by adhesive particles.
The length of the PCBA module is about 285mm measured by a ruler.
The width of the PCBA module is about 180mm.
The thickness of the PCBA module is about 17.6mm.
The power strip weighs about 585.5g.
The power strip is labeled with information
Name: Built-in switching power supply
Model: ZW9300-A
输入：100-240V~ 50/60Hz 3.8A Max
DC输出:5VSB0.5A,5V2A,12V2A,19V4A。
LED输出:80-240V 540-1200mA,LED功率≤150W。
Tunzhun ZW9300-A power board dismantling
After reading the appearance display of the power board of Dongzhun Electronics, let's disassemble it and take a look at the scheme and materials of this power board.
The front of the PCBA module is at a glance, and in the lower left corner is the power input terminal, which is equipped with a fuse, a common mode inductor and a safety X2 capacitor. The left heat sink is the rectifier bridge for heat dissipation. On the right side of the heat sink are thin film filter capacitors, filter inductors and PFC boost inductors. The heat sink on the right side is the PFC switch tube and rectifier tube for heat dissipation.
The upper right side of the heat sink is the high-voltage filter capacitor, the lower heat sink is the primary switch tube for heat dissipation, and the right side is the main transformer. There is a heat sink on the right side of the transformer to dissipate heat from the rectifier tube.
On the back of the PCBA module, the primary main control chip, LED dimming chip, LED dimming switch tube, switch tube for output control and other components are welded.
Through the observation of the PCBA module, it is found that the power board of Dongzhun Electronics adopts PFC+HFB switching power supply architecture with fixed voltage output. The output voltage is fed back by an optocoupler, and the power board is rectified with a Schottky diode and filtered by electrolytic capacitors.
The 5V output is powered by a step-down circuit board from a 12V step-down output, a switching power supply output of 12V and 19V, and an LED. The LED power supply adopts voltage doubling rectification, and the output is dimmed by the step-down circuit. The power strip 5V, 12V and 19V are equipped with MOS tubes for switching control.
Close-up of the AC input socket of the power strip.
Behind the socket is a fuse, the specification is 6.3A250V.
TVR10561 varistors are used to absorb overvoltage surges.
Common mode inductors are wound with enameled and insulated wires.
The safety X2 capacitor specification is 0.68μF.
Common mode inductors are wound with flat copper wire.
The two blue Y capacitors are from SHM Nanfang Hongming.
Ground terminal soldering connection.
The other common-mode inductor is also wound with flat copper wire.
Below the heatsink is a rectifier bridge.
The rectifier bridge is fixed to the heat sink using screws.
整流桥型号D15SB80，规格为15A800V。
The thin-film filter capacitor is from KNSCHA and is specified at 1μF 450V.
The filter inductor is magnetically wrapped.
The specifications of the two thin-film filter capacitors are 0.47μF 450V.
The primary controller is from Infineon, silkscreen mdp15, according to the pin definition, it is judged to be a XDPS2221 2-in-1 controller, a PFC+HFB 2-in-1 controller, with an integrated half-bridge driver in the chip, and a PG-DSP-14 package.
Below the long heat sink are PFC switches and PFC rectifiers.
Solder and remove the long heat sink, the left side is the PFC rectifier tube, and the right side is the two PFC switch tubes.
Two PFC switches are silkscreened SI18S60F in TO220F package.
Two 100mΩ resistors are used to sense the PFC switch current.
Close-up of PFC boost inductor, wound with litz wire.
The PFC rectifier is from ST STMicroelectronics, model number STTH8S06FP, 8A600V, and is available in a TO-220FPAC package.
The KBP310 rectifier bridge is used for PFC bypass to charge high-voltage capacitors.
The film capacitor specification is 0.022μF 630V and is used for output filtering.
The green NTC thermistor is used to suppress the inrush current of capacitor charging.
The two high-voltage filter capacitors are from AiSHi.
The specification is 450V 100μF.
A smaller heat sink dissipates heat from the HFB half-bridge switch.
The HFB half-bridge switch tube is screwed to the heat sink.
The switch is from Jilin Huawei, model JCS13N50F, NMOS, withstand voltage 500V, conduction resistance 460mΩ, TO-220MF package.
The resonant capacitor is from KNSCHA, which is MMKP82 series, with a specification of 0.015μF1000V, and two in parallel.
The filter capacitor that supplies power to the main control chip is 35V and 330μF.
The 8050 triode is used to supply regulated power to the main control chip.
The output filter capacitor specification is 35V100μF.
Close-up of the switching transformer, the core is insulated with tape, and the secondary is wound with litz wire.
Everlight EL817 optocoupler is used for output voltage feedback.
The blue Y capacitor comes from Nanfang Hongming.
Close-up of another blue Y-capacitor.
The long heat sink dissipates heat from the output rectifier tube.
Three Schottky diodes are fixed on the heat sink for output rectification.
The two Schottky diodes are from PY Pingwei, model PS20U60FCT, specification 60V20A, in ITO-220AB package.
The other is used for 19V output rectification, and the pin sleeve magnetic ring suppresses high-frequency interference.
Close-up of filter capacitors for 19V and 12V outputs.
The 19V output filter capacitor specification is 25V 470μF, and three are connected in parallel.
The 12V output filter capacitor specification is 25V 470μF, four in parallel, and the filter capacitor is from TOPAZCON Topaz.
The core inductor is used for 12V output filtering.
THE OUTPUT VOLTAGE FEEDBACK CHIP FROM DIODES, MODEL AP4310A, HAS DUAL OP AMPS AND VOLTAGE REFERENCES AND IS AVAILABLE IN AN SO-8 PACKAGE.
The 2mΩ sampling resistor is available in a 2512 package and is used to sense the power strip output current.
The 5V step-down circuit is a small independent board, vertically soldered, and powered by a 12V input.
Copper is exposed on the back of the small plate to enhance heat dissipation.
Synchronous step-down chip silk-screen printed NYCNF, integrated switch inside, in SOT23-6 package.
Close-up of 3.3μH buck inductor.
Two diodes are used for voltage doubling and rectification of the LED driver circuit.
The specifications of the four filter capacitors are 250V and 22μF.
LED driver chip silk screen printing ZW1208, is a switching step-down type constant current driver, using SOT23-6 package.
The other step-down chip is of the same model and corresponds to two LED drivers.
The two buck switches are not silk-screened and are available in a TO252 package.
Two chokes are used for the LED step-down drive.
Close-up of filter film capacitors and rectifier diodes.
Two thin-film capacitors from KNSCHA are specified at 1μF 450V and are used for LED output filtering.
Close-up of the jumper cap used to set the output current of the LED driver circuit, a total of six current levels can be set.
Close-up of LED output socket.
Close-up of LED output socket.
The silkscreen DS3912's NMOS transistor is used for 5V output control.
The MOS transistor for 12V output control is from Xinjieneng, model NCE40P40K, PMOS, withstand voltage -40V, conduction resistance 12mΩ, and is available in a TO-252-2L package.
The MOS transistor model for 19V output control is the same.
Summary of the dismantling of the charging head network
This power board is built-in, with a total output power of 300W, with 5V, 12V and 19V outputs, and also has a 150W LED backlight driver, the backlight driver current is adjustable, and supports dimming, which can power the computer and the screen at the same time. The power strip has multiple output interfaces, which can be adapted to different models.
The power board is designed with PFC+HFB architecture, using Infineon power chips, the primary switch tube is from Jilin Huawei, the Schottky diode is from Pingwei, and the corresponding power devices are equipped with heat sinks, which are fixed by welding. Among them, the high-voltage filter capacitor comes from Aihua, and the output filter capacitor comes from Topaz, and the overall workmanship and materials are solid.