This was the last (seventh) seminar of the less-than-two-weeks whirlwind tour of China. It delves into the fundamentals of control loop theory, providing numerical examples, and heading from analog-based loop compensation of switching power converters, to PID control. In the process, the author reveals his tested theory of Q-matching, to achieve the best transient response possible even under extreme line and load steps. This was proven to double the existing performance of the ZMDI (Zentrum Mikroelektronik Dresden AG) PID controllers. ZMDI was later acquired by Integrated Device Technology (IDT), San Jose, California, which is now Renesas. The idea was created by the author in the transition period and it slipped through the cracks of the IDT acquisition. But now you can see how simple the technique was, as it compares a PID controller to the impedance of a conventional capacitor, and thus finds the ideal compensation scheme possible. Never d