1. Field of the Invention
The instant disclosure relates to a current balance method and a current balance circuit; in particular, to a current balance method and a current balance circuit used in a multiphase digital pulse width modulator.
2. Description of Related Art
In recent years, the digital pulse width modulation technology has been widely used in the power management integrated circuit. Compared with the analog pulse width modulation technology, the digital pulse width modulation technology has lower cost and better features for controlling, which has made the digital pulse width modulation technology become main stream in the power control field in a short time.
On the other hand, compared with the traditional digital pulse width modulator with signal channel, the multiphase digital pulse width modulator has a plurality of parallel channels which can distribute the provided currents to each channel evenly. However, as the currents within the channels lose balance (for example, the current in certain channel is more than the currents in other channels), thermal runaway would happen and that channel would be thus burned. Therefore, there is still a current balance method needed to be used in the traditional multiphase digital pulse width modulator to make the currents distribute to each channel evenly so as to avoid the unbalance.
The current balance technology traditionally and commonly used in the traditional multiphase digital pulse width modulator is to detect the current of each phase and to calculate an average, so as to adjust the pulse width regarding to each phase. However, there is one analog to digital converter (ADC) needed for each phase to detect the current, which makes the analog to digital converter which has high converting rate and high transmission speed become rather important in the above traditional current balance method. Moreover, the above traditional current balance method has its working complexity.