Semiconductor device

1. A semiconductor device comprising:

a rectifier circuit that rectifies an AC input voltage;

a zero-cross detection circuit that detects a zero-cross of the AC input voltage; and

a control circuit that turns on the rectifier circuit at a timing determined by the zero-cross detected by the zero-cross detection circuit and a predetermined phase angle,

wherein the predetermined phase angle is set so that an output voltage of the rectifier circuit is gradually increased,

wherein the control circuit includes a zero-cross prediction circuit that predicts a next zero-cross timing from the zero-cross detected by the zero-cross detection circuit, and the timing of turning on the rectifier circuit is determined by the predicted next zero-cross timing and the predetermined phase angle.

2. The semiconductor device according to claim 1 , wherein the phase angle is set to be gradually increased.

3. The semiconductor device according to claim 2 , further comprising:

first and second input terminals that input the AC input voltage; and

first and second output terminals,

wherein the rectifier circuit includes first and second switching elements and first and second thyristors,

wherein the first switching element is disposed between the first input terminal and the first output terminal,

wherein the second switching element is disposed between the first input terminal and the second output terminal,

wherein the first thyristor is disposed between the second input terminal and the first output terminal,

wherein the second thyristor is disposed between the second input terminal and the second output terminal, and

wherein the control circuit controls turn-ons of the first and second thyristors.

4. The semiconductor device according to claim 3 ,

wherein a coil is disposed between the first input terminal and the first and second switching elements, and

wherein a capacitor is disposed between the first and second output terminals.

5. The semiconductor device according to claim 4 , wherein the control circuit performs a power factor correction by controlling the first and second switching elements when the phase angle reaches a predetermined value.

6. The semiconductor device according to claim 2 , further comprising:

first and second input terminals that inputs the AC input voltage; and

first and a second output terminals,

wherein the rectifier circuit includes first and second diodes and third and fourth thyristors,

wherein the first diode is disposed between the first input terminal and the first output terminal,

wherein the second diode is disposed between the second input terminal and the first output terminal,

wherein the third thyristor is disposed between the first input terminal and the second output terminal,

wherein the fourth thyristor is disposed between the second input terminal and the second output terminal, and

wherein the control circuit controls turn-ons of the third and fourth thyristors.

7. The semiconductor device according to claim 6 ,

wherein a second coil and a third diode are arranged in series between the first and second diodes and the first output terminal,

wherein a third switching element is disposed between a connection point of the second coil and the third diode and the second output terminal, and

wherein a capacitor is disposed between the first and second output terminals.

8. The semiconductor device according to claim 7 , wherein the control circuit performs a power factor correction by controlling the third and fourth thyristors and the third switching element when the phase angle reaches a predetermined value.

9. The semiconductor device according to claim 8 ,

wherein a third coil and a fourth diode are further arranged in series between the first and second diodes and the first output terminal, and

wherein a fourth switching element is disposed between a connection point of the third coil and the fourth diode and the second output terminal.

10. The semiconductor device according to claim 9 , wherein the control circuit performs a power factor correction by controlling the third and fourth thyristors and the third and fourth switching elements when the phase angle reaches a predetermined value.

11. The semiconductor device according to claim 2 , further comprising:

first and second input terminals that inputs the AC input voltage; and

first and a second output terminals,

wherein the rectifier circuit includes first and second diodes and third and fourth thyristors,

wherein the third thyristor is disposed between the first input terminal and the first output terminal,

wherein the fourth thyristor is disposed between the second input terminal and the first output terminal,

wherein the first diode is disposed between the first input terminal and the second output terminal,

wherein the second diode is disposed between the second input terminal and the second output terminal, and

wherein the control circuit controls turn-ons of the third and fourth thyristors.

12. The semiconductor device according to claim 11 ,

wherein a second coil and a third diode are arranged in series between the third and fourth thyristors and the first output terminal,

wherein a third switching element is disposed between a connection point of the second coil and the third diode and the second output terminal, and

wherein a capacitor is disposed between the first and second output terminals.

13. The semiconductor device according to claim 12 , wherein the control circuit performs a power factor correction by controlling the third and fourth thyristors and the third switching element when the phase angle reaches a predetermined value.

14. The semiconductor device according to claim 13 ,

wherein a third coil and a fourth diode are further arranged in series between the third and fourth thyristors and the first output terminal, further, and

wherein a fourth switching element is disposed between a connection point of the third coil and the fourth diode and the second output terminal.

15. The semiconductor device according to claim 14 , wherein the control circuit performs a power factor correction by controlling the third and fourth thyristors and the third and fourth switching elements when the phase angle reaches a predetermined value.