Self-Oscillating Current Mode Boost Converter (Discrete)

A Current-Mode Boost Converter works by using the ramp waveform obtained from sensing the switch current in conjunction with the error signal from the error amplifier in order to generate a PWM signal that drives the switch. This is a Self-Oscillating circuit in that it does not have a clock and a latch unlike conventional DC-DC converter circuits; instead, the circuit's error amplifier's output alone is used to generate a PWM in conjunction with the ramp waveform. I accidentally discovered the possibility to do this during the simulation stage of a Current-Mode Boost Converter with a clock. Advantage: A self-oscillating circuit is simpler due to the absence of a clock source and latch. Disadvantage: The PWM frequency is not fixed and is determined by the value of L, C input voltage, output voltage and load.   - --- Bill of Materials --- - Ref. Mfg. Part No. Description - 无序列表C2 -- -- capacitor, 100µF - 无序列表C3 -- -- capacitor, 100pF - 无序列表D3 OnSemi 1N5819 diode - 无序列表D4 OnSemi 1N4148 diode - 无序列表L1 -- -- inductor, 33µH, 5A pk - 无序列表M1 International Rectifier IRFZ44N MOSFET (I used IRF540N) - 无序列表Q1 NXP 2N3904 bipolar transistor - 无序列表Q2 NXP 2N3906 bipolar transistor - 无序列表Q3 NXP 2N3906 bipolar transistor - 无序列表Q4 NXP 2N3904 bipolar transistor - 无序列表R1 -- -- resistor, 10K - 无序列表R2 -- -- resistor, 470, 2W - 无序列表R8 -- -- resistor, 330m, 2W - 无序列表R9 -- -- resistor, 50K - 无序列表R10 -- -- resistor, 10K - 无序列表R12 -- -- resistor, 470, 2W - 无序列表R13 -- -- resistor, 4.7 - 无序列表R14 -- -- resistor, 3.3K - 无序列表R15 -- -- resistor, 10K - 无序列表R16 -- -- resistor, 100 - 无序列表R17 -- -- resistor, 10K - 无序列表R18 -- -- resistor, 10K - 无序列表R19 -- -- resistor, 10K - 无序列表R20 -- -- resistor, 3.3K - 无序列表R22 -- -- resistor, 100K - 无序列表R24 -- -- resistor, 100K - 无序列表*For U2, U3 and U5, use TL074* - 无序列表U2 Analog Devices LT1056 integrated circuit - 无序列表U4 Analog Devices LT1077 integrated circuit - 无序列表U5 Analog Devices LT1077 integrated circuit