CURRENT DRIVER, LED DRIVE CIRCUIT, LIGHTING DEVICE AND ELECTRONIC APPARATUS

摘要

A current driver connected with light emitting diode (LED) bars of the maximum number N of channels and driving LED bars of M channels to be driven, includes: PWM input terminal configured to receive PWM-modulated external dimming pulse having duty cycle with a target light quantity common to the LED bars of the M channels; pulse measurement circuit configured to measure period and pulse width of the external dimming pulse and generate digital period data and pulse width data; interface circuit connected to external processor and configured to receive enable data and phase difference setting data; M current sources of the M channels to be driven and respectively connected with corresponding LED bars, and configured to be On-and-Off-switched in response to internal dimming pulse; and pulse generator configured to generate M internal dimming pulses and distribute the M internal dimming pulses to the M current sources.

主权项

1. A current driver which is connected with light emitting diode (LED) bars of the maximum number N of channels (N is an integer of 2 or more) and drives LED bars of M channels (1≦M≦N) designated to be driven, comprising:
a PWM input terminal configured to receive an external dimming pulse subjected to pulse width modulation (PWM), the external dimming pulse having a duty cycle according to a target light quantity common to the LED bars of the M channels; a pulse measurement circuit configured to measure a period and a pulse width of the external dimming pulse and generate a digital period data and a pulse width data; an interface circuit which is connected to an external processor and is configured to receive (i) an enable data to designate the LED bars of M channels to be driven and (ii) a phase difference setting data to designate one of a plurality of selectable phase differences 360°/2, 360°/3, . . . , 360°/N; a plurality of M current sources which correspond to the M channels to be driven and are respectively connected with corresponding LED bars, and which are configured to be switched between On and Off in response to an internal dimming pulse; and a pulse generator configured to generate M internal dimming pulses having a period represented by the period data, a pulse width represented by the pulse width data, and a phase difference according to the phase difference setting data, and to distribute the generated M internal dimming pulses to the M current sources.