AC Input ──► [EMI Filter] ──► [Bridge Rectifier] ──┬──► [Boost Stage A] (0°) ──┬──► DC Out └──► [Boost Stage B] (180°) ──┘
Contains dual Over-Current Protection (OCP1/OCP2), Dynamic and Static Over-Voltage Protection (OVP), and Feedback Loop Absence Detection. Enhanced Thermal Balance: Implements an internal
The workshop was silent except for the rhythmic tick-tick-tick of the wall clock, a stark contrast to the frantic energy usually surrounding Elias, the lead repair technician. On his anti-static mat sat a vintage 1980s industrial controller—the "
To explore the low-level electrical parameters or safety bounds of this controller, you can review the official .
Typically utilizes large capacitors (ranging from 1000uF to 4700uF) to smooth out the pulses and reduce voltage ripple.
The core of this circuit is a . The R2A20112 uses a "Constant ON Time" control method. This means that the controller keeps the transistor's on-time fixed and varies its off-time to regulate the output voltage to a stable level (e.g., 390V DC). By smoothing the resulting inductor current, it creates a current waveform that is perfectly in phase with the input voltage, achieving high power factor.
This is the heart of the A20112 schematic. It ensures the output voltage remains constant despite fluctuations in input voltage or changes in load current.
The IC controls a boost converter to provide active power factor correction, which is essential for efficiency in larger power supplies. Renesas Electronics Critical Conduction Mode (CRM):
: Converts AC mains voltage to high-voltage DC .
Final notes
🔍 Need the actual A20112 schematic? Search the full part number (including manufacturer suffix) on , ElectroTanya , or Badcaps.net forums .
High-voltage smoothing capacitors can hold a lethal charge long after the unit is unplugged. Always verify zero voltage with a multimeter, or discharge them safely using a high-wattage resistor.
: Unlike proprietary power bricks, the A20112 is a bare-board or aluminum-cased switching mode power supply (SMPS) designed for integration into larger projects . It is prized for its 120W capacity , allowing it to handle high-power demands—like heating a 3D printer's bed or running multiple security cameras—without failing .
A slow-blow fuse protects the unit from overcurrent scenarios caused by shorted components downstream.
If your A20112 outputs 9V or 15V, check R24 and R25 for drift or cold solder.
