Boosting circuit, backlight driving circuit and backlight module

摘要

A boosting circuit, a backlight driving circuit and a backlight module are provided. The boosting circuit comprises a boosting chip (U1), an energy-storage inductor (L1), a freewheeling diode (D1), a first capacitor (C1), and a current mirror unit (U2), wherein an input terminal of an inputting branch of the current mirror unit (U2) IS connected with the cathode of the freewheeling diode (D1), and an output terminal of the inputting branch is connected with the signal input terminal (Vin) of the boosting circuit through a first resistor (R1), an input terminal of an outputting branch of the current mirror unit (U2) IS connected with the cathode of the freewheeling diode (D1), an output terminal of the outputting branch is grounded through a second resistor (R2), an ungrounded terminal of the second resistor (R2) is connected with a signal feedback pin of the boosting chip. The boosting circuit realizes the tracking of changes of the input voltage by the output voltage under the precondition that parameters of respective elements are unchanged, and achieves the effect that a voltage difference between the output voltage and the input voltage is fixed.

主权项

1. A boosting circuit, comprising a boosting chip, an energy-storage inductor, a freewheeling diode and a first capacitor, in which one terminal of the energy-storage inductor is connected with a signal input terminal of the boosting circuit, the other terminal thereof is connected with a pin of large current switch of the boosting chip and is further connected with a signal output terminal of the boosting circuit through the freewheeling diode; one terminal of the first capacitor is connected with a cathode of the freewheeling diode, and the other terminal is grounded; wherein:
the boosting circuit further comprises a current mirror unit, an input terminal of an inputting branch of the current mirror unit is connected with the cathode of the freewheeling diode, and an output terminal of the inputting branch is connected with the signal input terminal of the boosting circuit through a first resistor; an input terminal of an outputting branch of the current mirror unit is connected with the cathode of the freewheeling diode, and an output terminal of the outputting branch is grounded through a second resistor, where an ungrounded terminal of the second resistor is connected with a signal feedback pin of the boosting chip.