BOSHIDA Basic knowledge of power modules
Output Voltage Regulation
For module power products with TRIM or ADJ (adjustable) output pins, the output voltage can be adjusted within a certain range through a resistor or potentiometer, and the general adjustment range is ±10%.
For the TRIM output pin, connect the center of the potentiometer to TRIM, and in all +S, -S pin modules, connect the other two ends to +S, -S respectively. When there is no +S, -S, connect the two ends to the output positive and negative poles of the corresponding main circuit (+S to +Vin, -S to -Vin), and then adjust the potentiometer. The resistance value of the potentiometer is generally selected from 5 to 10kΩ, which is more appropriate.
For the ADJ output pin, it is divided into input side regulation and output side regulation. The output edge is adjusted in the same way as the TRIM pin. The input side adjustment can only increase the output voltage. At this time, one end of the potentiometer is connected to the center, and the other end is connected to the ground of the input end.
Input protection circuit
General module power supply products have built-in filters, which can meet the requirements of general power supply applications. If a power system with higher requirements is required, the input filter network should be added. LC or π-type network can be used, but care should be taken to choose a smaller inductance and a larger capacitance as much as possible.
In order to prevent the transient high voltage of the input power supply from damaging the module power supply, it is recommended that the user connect a transient absorption diode to the input terminal and use it with a fuse to ensure that the module is within a safe input voltage range. In order to reduce the common mode noise, you can increase the Y (Cy) capacitor, generally choose several nf high-frequency capacitors. R is a fuse, D1 is a protection diode, and D2 is a transient absorption diode (P6KE series).
Remote switch circuit
The remote switch operation of the module power supply is carried out through the REM terminal. There are two general control methods:
(1) REM is connected to -VIN (reference ground), and remote control is turned off, requiring VREF<0.4V. REM is suspended or connected to +VIN, and the module works, requiring VREM>1V.
(2) REM is connected with VIN, and remote control shuts down, requiring VREM<0.4V. REM is connected to +VIN, and the module works, requiring VREM>1V. REM is suspended, and the remote control is turned off, which is the so-called “suspended shutdown” (-R).
If the control is to be isolated from the input, an optocoupler can be used to pass the control signal.
Output Voltage Regulation
For module power products with TRIM or ADJ (adjustable) output pins, the output voltage can be adjusted within a certain range through a resistor or potentiometer, and the general adjustment range is ±10%.
For the TRIM output pin, connect the center of the potentiometer to TRIM, and in all +S, -S pin modules, connect the other two ends to +S, -S respectively. When there is no +S, -S, connect the two ends to the output positive and negative poles of the corresponding main circuit (+S to +Vin, -S to -Vin), and then adjust the potentiometer. The resistance value of the potentiometer is generally selected from 5 to 10kΩ, which is more appropriate.
For the ADJ output pin, it is divided into input side regulation and output side regulation. The output edge is adjusted in the same way as the TRIM pin. The input side adjustment can only increase the output voltage. At this time, one end of the potentiometer is connected to the center, and the other end is connected to the ground of the input end.
Input protection circuit
General module power supply products have built-in filters, which can meet the requirements of general power supply applications. If a power system with higher requirements is required, the input filter network should be added. LC or π-type network can be used, but care should be taken to choose a smaller inductance and a larger capacitance as much as possible.
In order to prevent the transient high voltage of the input power supply from damaging the module power supply, it is recommended that the user connect a transient absorption diode to the input terminal and use it with a fuse to ensure that the module is within a safe input voltage range. In order to reduce the common mode noise, you can increase the Y (Cy) capacitor, generally choose several nf high-frequency capacitors. R is a fuse, D1 is a protection diode, and D2 is a transient absorption diode (P6KE series).
BOSHIDA Basic knowledge of power modules
Remote switch circuit
The remote switch operation of the module power supply is carried out through the REM terminal. There are two general control methods:
(1) REM is connected to -VIN (reference ground), and remote control is turned off, requiring VREF<0.4V. REM is suspended or connected to +VIN, and the module works, requiring VREM>1V.
(2) REM is connected with VIN, and remote control shuts down, requiring VREM<0.4V. REM is connected to +VIN, and the module works, requiring VREM>1V. REM is suspended, and the remote control is turned off, which is the so-called “suspended shutdown” (-R).
If the control is to be isolated from the input, an optocoupler can be used to pass the control signal.
