| 摘要 |
A power supply. The power supply comprises: a drive switch transistor (Q101). The power supply also comprises: a transformer (T101) that has a specific sense quantity, wherein the transformer (T101) that haves a specific sense works in discontinuous current mode or a critical mode under a rated load; a voltage and current control loop (10), used for sampling an output voltage and an input current of the transformer (T101), feeding back a sampled voltage when the output voltage is higher than a preset value, and feeding back a sampled current when the output voltage is not higher than the preset value; and a PWM control circuit (20), used for performing, by means of the drive switch transistor (Q101), voltage stabilization adjustment on the transformer (T101) according to the sampled voltage or the sampled current, and for enhancing the work frequency of the transformer (T101) by means of the drive switch transistor (Q101) when the output voltage is not higher than the preset value. |
