Critical continuous boost converter employing constant-frequency control

The invention discloses a critical continuous boost converter employing a constant-frequency control. The critical continuous boost converter employing the constant-frequency control comprises a main power circuit and a control circuit. The control circuit comprises a first bleeder circuit, a second bleeder circuit, a subtraction circuit, a multiplying unit, an error regulating circuit, a CRM control, and a drive circuit. An input terminal of the first bleeder circuit is connected with an input voltage sampling point; an output terminal of the first bleeder circuit is respectively connected with an inverted input terminal of the subtraction circuit and a first input terminal of the multiplying unit. An input terminal of the second bleeder circuit is connected with the anode of an output voltage of the main power circuit; an output terminal of the second bleeder circuit is connected with a normal phase input terminal of the subtraction circuit. An output terminal of the subtraction circuit is connected with a second input terminal of the multiplying unit. An inverted input terminal of the error regulating circuit is connected with the anode of the output voltage; a normal phase input terminal of the error regulating circuit is connected with a voltage benchmark signal; and an output terminal of the error regulating circuit is connected with the CRM control and one input terminal of the drive circuit. An output terminal of the multiplying unit is connected with the CRM control and the other input terminal of the drive circuit. A switching frequency of the critical continuous boost converter employing the constant-frequency control remains constant in a fundamental frequency cycle with a small frequency variation range.