US 12,438,468 B2
Insulated power supply apparatus and semiconductor device for power supply control
Daisuke Imade, Isehara (JP); Hiroki Matsuda, Zama (JP); Takumi Hyugaji, Isehara (JP); and Yukio Murata, Tokyo (JP)
Assigned to MITSUMI ELECTRIC CO., LTD., Tokyo (JP)
Filed by Daisuke Imade, Isehara (JP); Hiroki Matsuda, Zama (JP); Takumi Hyugaji, Isehara (JP); and Yukio Murata, Tokyo (JP)
Filed on Jul. 7, 2023, as Appl. No. 18/348,405.
Claims priority of application No. 2022-109659 (JP), filed on Jul. 7, 2022; and application No. 2023-092251 (JP), filed on Jun. 5, 2023.
Prior Publication US 2024/0014741 A1, Jan. 11, 2024
Int. Cl. H02M 3/335 (2006.01)
CPC H02M 3/33507 (2013.01) [H02M 3/3353 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An insulated power supply apparatus comprising:
a transformer for voltage conversion;
a switching element connected in series with a primary-side winding of the transformer;
an active clamp circuit connected between terminals of the primary-side winding of the transformer; and
a semiconductor device for power supply control that controls the switching element and the active clamp circuit,
wherein a current-to-voltage converter element is connected in series with the switching element,
wherein the semiconductor device for power supply control includes:
a circuit that generates a timing to turn off the switching element based on a voltage obtained by conversion by the current-to-voltage converter element and a predetermined turn-off threshold level;
a circuit that performs ON/OFF control of the switching element in a burst mode at a predetermined load or less; and
a circuit that, in the burst mode, changes a burst frequency to be lower as a load current is smaller with a number of switching times of the switching element in one burst cycle fixed,
wherein in a region of a load greater than the predetermined load, the ON/OFF control of the switching element is performed in a continuous operation mode, and
wherein in the burst mode, in a partial range close to the continuous operation mode, control is performed such that a change rate of the burst frequency is made larger, and in a range except the partial range, control is performed such that the change rate of the burst frequency is made smaller.