The AP combines a Pulse Width Modulation. (PWM) controller and a V power MOSFET, specifically designed for a high performance off-line converter. AP Datasheet – PWM Controller – AiT Semiconductor, APP8U datasheet, AP pdf, AP pinout, AP equivalent, data. Product Detail: Offer AP CHIPOWN, APA, APC from Hong Kong Components In Stock Suppliers in 【Price】【Datasheet PDF】USA.
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It is dedicated for building an auxiliary power supply based on the VIPer12AS monolithic device with rather low output power required. In this case the converter should be simple and low cost. The presented power supply has two variants.
APH APC/AP Low Power OFF-Line SMPS Primary Switcher SOP-8
The first is a buck step-down converter with a positive output voltage referenced to the common ground. The second one with negative output voltage is a buck-boost converter.
The presented reference board incorporates both variants by different assembly options. The output of the converter is not isolated from input.
For this reason the reference ground is common for an input and output connection terminal. The input capacitor C1 is charged from line via one way rectifier consisting of diodes D1 and D2. Two diodes in series are used for EMI reasons to sustain burst pulses of 2kV. It means the IC and corresponding supply and feedback loop circuitry is floating. The voltage feedback loop is provided via zener diode D3, resistor R3 and capacitor C6.
The diode D7 between capacitor C7 and C4 ensures the proper start-up of the converter.
AP8012 Datasheet PDF – Chipown
Thanks to this diode the feedback loop circuit is separated from supply circuit. The internal start-up current source of the VIPer12 charges the IC supply capacitor C4 to a specified start-up threshold voltage of about 16V. The inductor keeps the direction of the current flowing and it reverses the voltage at C3. The inductor current then flows through the forward biased D5 diode and charges the output capacitor C3. In this switch-off phase the source terminal of the VIPer12 sees a negative level of the forward biased D5 when referenced to ground so it can be considered as grounded.
AP8012 – GREEN POWER OFF LINE SMPS PRIMARY SWITCHE
This allows the inductor current to flow also through D4 and supply the VIPer12 and give the feedback information about output voltage. Resistor R3 limits the feedback current to a safe value lower than the maximum rating specified in the data sheet. One has to take into account the slight variation of the output voltage with the load. It is because the feedback current reacts to the output load change to adopt switching duty cycle.
The variable feedback current creates ap812 FB voltage, different voltage drop across fatasheet resistor R3 and D3 zener voltage. The feedback current can change from 0mA full output power to about 0. The R3 voltage variation is 0. The D3 voltage variation depends on the diode V-I characteristics.
Diode D6 limits the output voltage at light load condition and it also protects the U2 voltage regulator. Regulator U2 accommodated in DPAK or SO-8 package is optional and can be assembled if the power supply for a microcontroller or logic part is required. The assembled board contains both SMD and through hole components.
The board incorporates both a buck and buck-boost variant of the converter. The outline dimensions are 38x29mm. Assembly top side trough-hole components and solder bottom SMD components side can be seen in Figure 2 and Figure 3.
Assembly Top not in scale Figure 3: Assembly Solder Side not in scale Figure 4: The holes for through-hole components are not seen in the picture.
The physical appearance of the converter can be observed from Figure 5. Picture of the Converter 2. It shows the variation of the output voltage with output current at specific DC input voltage. The zener diode D6 was not connected during the measurements Figure 6: Figure 7 datasbeet the variation of the output voltage with input DC voltage change. The output current is the parameter in this case.
Figure 8 depicts the dependency of the efficiency on the input voltage parameter is output current while Figure 9 shows the dependency on the output current parameter is input voltage. Channel 4 red shows the inductor current. The purpose of those pictures is to demonstrate the skipping cycle function at light or no-load condition and cycle-by-cycle primary current limitation at overload or output shorted condition.
The measurements were performed at VAC input voltage and the 15V output was fully loaded by mA load. wp8012
The presented results depicted from Figure 18 to Figure 21 show the results. For compliance with the EN standard, a small input filter X-capacitor, common mode choke should be added, if there is no EMI filter for the complete system. Alternatively, a double sided pcb can be used. Phase L, average detector Figure Phase L, peak detector Figure Phase N, average detector Figure Phase N, peak detector 2. The output current flowing to the output capacitor C3 is discontinuous for the buck-boost converter unlike the above described buck converter.
During primary switch ON-time the inductor current flows through the inductor to ground and not to the output capacitor as for buck converter. As soon as the primary switch is turned off, the inductor reverses the voltage between its terminals and current starts to flow through the forward biased D5 diode and charges the output capacitor C3.
In this switch-off phase the source terminal of the VIPer12 sees negative level of forward biased D5 and negative output voltage when referenced to ground. The converter is called inverting. It is because the output voltage is negative compared to the input voltage referred to the same common ground.
By removing the jumper R5 and placement of the jumper R4 the buck converter can be easily changed to the inverting buck-boost converter. The zener diode D6 was not connected during the measurements.
Figure 24 shows the variation of the output voltage with input DC voltage change. The channel 4 red shows the inductor current. One should notice the negative voltage datasheet on the VIPer12 source after internal switch turn-off.
The level of this negative voltage is equal to the output voltage level. The way, how the reference board can be easily switched between two basic non-isolated topologies buck and buck-boost converter was described.
Depicted output regulation and overall converter efficiency characteristics measured at different working conditions show ap8021 performance of this simple VIPer12AS application in such difficult working environment.
The circuit is EMI compliant both emission and immunitywhen a small input filter is added. Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may results from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice.
This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.