+5V to -5V power module based on MC34063

Update: Proofing verification completed

MC34063ADR can realize the functions of boost, step-down and inversion of power supply. This project uses voltage inversion as an example to design the corresponding circuit. Using +5V input, the -5V voltage commonly used in op amp chips is obtained. The design parameters are as follows:

1. Parameter settings related to the working status of the chip (can be changed, but the parameters of related components in the circuit will also change accordingly): input voltage 5V, output -5V, maximum output current 200mA, output voltage ripple 20mVpp, chip operating frequency 75kHz
2. Relevant component parameters in the circuit: Ct=306pF, Rsc=0.319Ω, Lmin=33μH, Co=689μF, the voltage sampling resistance at pin 5 is 1kΩ, 3kΩ respectively (the relevant parameters in the actual circuit are approximate values)

Notice:

• In the previous circuit, the order of the two voltage sampling resistors at chip pin 5 was reversed, which would result in an output of about -1.68V (really careless). If the order is reversed, it will work normally. The changes have been made and used in the PCB. The silk screen marks the specific resistance value to prevent errors.

• • -

The picture below is an empty board picture

The picture below is a physical picture of the completed welding process.

Voltage measurement is correct