Electromagnetic heating control circuit and electromagnetic heating device

An electromagnetic heating control circuit, comprising:

• a control chip, a rectifying and filtering circuit, a resonance capacitor, a switch transistor, a drive circuit, and a synchronous voltage detection circuit, wherein:
• the switch transistor comprises a first terminal, a second terminal, and a control terminal configured to control a connection state between the first terminal and the second terminal, the first terminal is connected to a positive output terminal of the rectifying and filtering circuit via the resonance capacitor, the second terminal is connected to a negative output terminal of the rectifying and filtering circuit via a current-limiting resistor;
• and
• the control chip comprises a non-inverting voltage input terminal, an inverting voltage input terminal, a voltage detection terminal, and a signal output terminal, the non-inverting voltage input terminal and the inverting voltage input terminal detect voltages at two terminals of the resonance capacitor via the synchronous voltage detection circuit, the signal output terminal is connected to the control terminal via the drive circuit, the voltage detection terminal is connected to the positive output terminal of the rectifying and filtering circuit via the synchronous voltage detection circuit, the control chip is configured to control a work state of the switch transistor according to a voltage detected by the voltage detection terminal, and to control, according to voltages of the non-inverting voltage input terminal and the inverting voltage input terminal, the switch transistor to turn on when a voltage at a connection node between the resonance capacitor and the switch transistor is zero.

An electromagnetic heating control circuit, comprising:

• a drive circuit, a protection circuit, and a switch transistor, wherein:
• the switch transistor comprises a first terminal, a second terminal, and a control terminal configured to control a connection state between the first terminal and the second terminal, the control terminal is connected to a signal output terminal of the drive circuit, and the second terminal is connected to a ground terminal;
• the drive circuit is connected to a control chip, and configured to magnify a pulse width modulation signal received from the control chip and to output a magnified pulse width modulation signal to the switch transistor via the signal output terminal of the drive circuit, so as to drive the switch transistor;
• the drive circuit is configured to detect an output voltage value of the signal output terminal, and to adjust a state of the magnified pulse width modulation signal output by the signal output terminal according to whether the output voltage value of the signal output terminal is within a preset interval range;
• and
• the protection circuit is configured to control a work state of the switch transistor according to a voltage value of the first terminal when the switch transistor is turned off, or the protection circuit is configured to control the work state of the switch transistor according to a detected current value of the second terminal when the switch transistor is turned on.

An electromagnetic heating circuit, comprising a coil, a resonance capacitor, a control chip, a drive module, a protection module, and a switch transistor, wherein:

• the coil is connected in parallel to the resonance capacitor;
• the switch transistor comprises a first terminal, a second terminal, and a control terminal configured to control a connection state between the first terminal and the second terminal, the control terminal is connected to a signal output terminal of the drive module, the first terminal is connected to a terminal of the resonance capacitor, and the second terminal is connected to a ground terminal;
• the control chip is configured to output a pulse width modulation signal to the drive module, the pulse width modulation signal is output to the switch transistor via the signal output terminal of the drive module, so as to drive the switch transistor;
• and
• the protection module is configured to control a work state of the switch transistor according to a voltage value of the first terminal when the switch transistor is turned off, or the protection module is configured to control the work state of the switch transistor according to a detected current value of the second terminal when the switch transistor is turned on.