A Direct Current-Direct Current (DC-DC) converter is a circuit topology using which an input direct current voltage is converted into an output direct current voltage. According to a buck-boost characteristic of a system, the DC-DC converter may fall into several main types, such as a boost type, a buck type, and a buck-boost type. Generally, a low-power DC-DC converter uses a buck structure and a boost structure. Compared with a conventional linear power system, a buck DC-DC converter has higher conversion efficiency and saves more energy. The efficiency may be at least 80%. The buck DC-DC converter is widely used in various products of a mobile base station and a consumer terminal.
In an existing relatively mature DC-DC converter, modulation modes such as pulse-width modulation (PWM) and pulse-frequency modulation (PFM) are generally used such that the DC-DC converter can maintain stable performance in different operating conditions. The PWM modulation mode of the DC-DC converter further falls into a voltage-mode control manner, a current-mode control manner, and a hysteresis-mode control manner. A current-mode controlled DC-DC converter may have a fixed frequency and is suitable for multiphase parallel connection. However, the current-mode controlled DC-DC converter has a complex structure, a poor antinoise capability, and a poor load transient response. A voltage-mode controlled DC-DC converter may also have a fixed frequency. However, the voltage-mode controlled DC-DC is not suitable for multiphase parallel connection, has a complex internal compensation circuit, and wastes more areas. A hysteresis-mode controlled DC-DC converter has a simple structure, and a fast-speed load transient response. However, it is hard to fix a frequency.
In a current commercial power system, a consumer terminal has an increasingly higher requirement for conversion efficiency and a transient response capability that are of the power system. Limited by a structure, the current-mode controlled DC-DC converter and the voltage-mode controlled DC-DC converter cannot meet a requirement of a customer. Because it is hard for the hysteresis-mode controlled DC-DC converter to have a fixed operating frequency, the hysteresis-mode controlled DC-DC converter cannot meet a requirement of a frequency-sensitive load.