DC-DC converter schematic diagram

Tags: DC-DC converter schematic transformer coupler

Figure 48-12V DC-DC converter schematic diagram

working principle:

The picture below is based on the physical analysis. The power supply provides a voltage of about +12V to IC 1 through D2 and R1. The 6-pin output pulse is coupled with C4 and the transformer to drive Q1 to oscillate. When Q1 is turned on, the output current passes through L and is filtered by C9. Power is supplied to the load backward. When Q1 is cut off, the magnetic energy of the transformer-type inductor B3 is converted into electrical energy. Its polarity is negative on the left and positive on the right. The freewheeling diode D4 is turned on, and the current continues to supply power to the load through the diode, so that the load receives a smooth DC. When the output voltage is too low or too high, the sampling voltage is obtained from the voltage dividing circuit composed of resistors R11, R10, and R9 and sent to pin 2 of IC1. After comparing it with the internal 2.5V reference voltage, the Q1 conduction pulse width is controlled, so that the output voltage is Stablize. When the load current is short-circuited or exceeds 8A, the rise in the voltage at pin 3 of IC 1 will control the pulse width to cut off Q1 to ensure the safety of Q1.

C8 and R7 constitute the oscillation time constant. The oscillation frequency of this circuit is 65KHz. Its calculation formula is as follows: