DC-DC booster

As shown in the picture is a cheap 5V to 12V voltage regulator circuit. A DC-DC converter is composed of six inverters, including an oscillator, power switch and error amplifier.

The load regulation rate of this circuit is better than 1%, and the output voltage only changes 7% when the temperature increases from 0 degrees to 50 degrees. IC-l and IC-2 form an oscillator, and the switching frequency is less than 1MHz. The oscillator output drives parallel inverters IC-3, IC-4, and IC-5. The parallel output has higher switching current and output power. The internal output transistor of the IC forms an enhanced converter with L1 and VD1. When the output is low level, the lower part of L1 is grounded, and the current flowing through the coil increases; when the output is high level, energy is stored in the coil to promote the positive voltage of VD1 rises, VD1 is turned on and charges C1, causing the voltage across C1 to rise to 12V. IC-6 plays a regulating role and uses feedback resistors R1 and R2 to monitor the output voltage. When the output rise causes the input of IC-6 to exceed the TTL threshold (about 1.2V), the output of IC-6 turns to low level, causing the output stage to stop working. When the output voltage drops below 12V, IC-6 causes the oscillator to drive the power switch.

The output current of each inverter should not exceed 40mA, and 120mA can be obtained by connecting three levels in parallel.

L1 in the picture is a chip inductor, the size is 2mmx2.5mm, and the model is Panasonic PINELT-PC130KF.