US 11,923,833 B2
Switch driving device
Kenji Hama, Kyoto (JP); and Takahiro Kotani, Kyoto (JP)
Assigned to ROHM CO., LTD., Kyoto (JP)
Appl. No. 16/978,113
Filed by ROHM CO., LTD., Kyoto (JP)
PCT Filed Jan. 15, 2019, PCT No. PCT/JP2019/000814
§ 371(c)(1), (2) Date Sep. 3, 2020,
PCT Pub. No. WO2019/193805, PCT Pub. Date Oct. 10, 2019.
Claims priority of application No. 2018-071136 (JP), filed on Apr. 2, 2018.
Prior Publication US 2021/0044290 A1, Feb. 11, 2021
Int. Cl. H03K 17/081 (2006.01); H02M 1/08 (2006.01); H03K 17/06 (2006.01)
CPC H03K 17/08104 (2013.01) [H02M 1/08 (2013.01); H03K 17/063 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A switch driving device, comprising:
a gate driver configured to drive an N-type semiconductor switch element;
a current limiter configured to limit a current fed to a boot capacitor included in a bootstrap circuit configured to apply a voltage to the gate driver; and
a current controller configured to control operation of the current limiter,
wherein
the current controller is configured to drive the current limiter to limit the current fed to the boot capacitor when a charge voltage across the boot capacitor is higher than a threshold value,
the current controller is configured to judge whether the boot capacitor is being charged or not and to sense the charge voltage across the boot capacitor, and
the current controller is configured to drive the current limiter when, while the boot capacitor is being charged, the charge voltage across the boot capacitor becomes higher than the threshold value.