I. Introduction The single-transistor buck power supply shown in Figure 1 has a simple topology, but driving it is not easy because the source potential of the MOSFET is not fixed. This article analyzes and compares different driving methods for chopper power supplies in terms of circuit complexity, driving pulse quality, cost, and adaptability to operating frequency. II. Analysis of Various Driving Circuits 1. Level Conversion Direct Driving: When the supply voltage of the main circuit is not too high, the level conversion driving circuit shown in Figure 2 can be inserted. The advantage of this method is its low cost. The disadvantages are: firstly, it is not easy to handle when the input voltage Vin is high; secondly, the level shifting driving part requires a charge pump, so the circuit is relatively complex. 2. Optocoupler Isolated Driving: This is a commonly used method, as shown in Figure 3. The advantage is that the circuit is relatively mature, but the optocoupler secondary requires an isolated power supply. Since the optocoupler is not very fast, the operating frequency cannot be too high, and it may reduce the transient response speed of the power supply. 3. Direct Driving by Changing the MOSFET Position: As shown in Figure 4, by moving the MOSFET to the negative terminal of the power supply, it can be directly driven by the signal output by the IC. The advantages are low driving cost, but the disadvantages are: firstly, the output ground is floating, resulting in poor anti-interference; secondly, feedback cannot be directly introduced, requiring additional optocoupler isolation for transmission. 4. Transformer Direct Isolation Drive: As shown in Figure 5, the outstanding advantage of this direct drive method is its lowest cost. However, since the transformer can only transmit AC signals, the amplitude of the output positive and negative pulses varies with the duty cycle, making it only suitable for duty cycles around 0.5 with minimal variation. Additionally, since the transformer's load is the input capacitor of the MOSFET, the leading and trailing edges of the drive pulses are generally not ideal. 5. Active Transformer Drive: The transformer transmits the signal, with an additional isolation power supply and amplifier circuit on the secondary side, as shown in Figure 6. Because the transformer only transmits the signal, the response is relatively fast, and the operating frequency can be very high. The secondary side is active, allowing for the output of relatively steep pulse signals. The disadvantage is the need for an isolated power supply. 6. Direct Drive Using a New Type of Isolation Drive Component: Figure 7 shows a chopper circuit using the KD103 (formerly CMB3) type drive module. This drive component is a single-transistor isolation driver developed by Beijing Luomuyuan Company. This driver uses transformer isolation and employs time-sharing technology, transmitting the PWM signal on the rising and falling edges of the input signal and transferring energy during the flat-top phase, thus enabling the output of steep drive pulses. The advantages of this driving method are ease of use (when the MOSFET power is low, the connection as shown in Figure 7 is sufficient), good drive pulse quality, high operating frequency, small size, input voltage up to 1000V, and relatively low price. The disadvantages are that the required transformer is larger at lower operating frequencies, and the cost is slightly higher. However, considering the simplified design and reduced assembly costs, the overall cost may be lower. III. Conclusion The table below summarizes the above analysis. It can be seen that in most cases, using the KD103 (formerly CMB3) dedicated chopper isolation driver is the better choice.