Cantor Colburn LLP
Control circuit for switching power supply
A control IC controls a switching power supply configured to supply a driving voltage Vout to one terminal of an LED string to be intermittently driven. In the on period of the LED string, a pulse modulator generates a pulse signal having a duty ratio adjusted such that a detection voltage VLED that corresponds to the output voltage Vout of the switching power supply matches a predetermined reference voltage Vref. A driver drives a switching transistor included in the switching power supply according to the pulse signal. After transition from the on period to the off period, the pulse modulator reduces the duty ratio of the pulse signal over time.
Rohm Co., Ltd.
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H05B H02M G09G H05B G09G Y02B G09G H02M
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Daisuke Hiroki
Uchimoto Kikuchi