This section introduces the implementation of Peak Current Mode (PCM) PWM signal generation in a Buck converter using TPLD. As shown in Figure 5, the host controller or an external operational amplifier provides the compensated error signal. TPLD utilizes its internal comparator to compare this error signal with the triangular inductor current waveform, generating an initial comparator output. This output is then processed by an RS flip-flop synchronized with the clock signal to establish the initial PWM waveform. Finally, the internal logic circuitry generates complementary PWM outputs.

Figure 3-3 illustrates a simplified control block diagram. In practical designs, the overall performance and reliability of this implementation can be enhanced through the following methods:

1. When the duty cycle exceeds 50%, slope compensation must be introduced to the current sensing signal derived from the clock to prevent subharmonic oscillation
2. Internal comparators or additional logic circuitry can be utilized to construct maximum duty cycle limiting and cycle-by-cycle overcurrent protection circuits
3. For high-frequency applications, an external high-speed comparator can be employed to achieve faster transient response.