Abstract: A control circuit of a driving circuit for supplying a driving current to a light source includes: a pulse width modulation (PWM) input terminal configured to receive an input dimming pulse having an input duty ratio corresponding to a target light quantity of the light source, the input dimming pulse being pulse-width modulated; and a dimming controller configured to convert a period and a pulse width of the input dimming pulse into digital values, reconvert the digital values into an output dimming pulse having an output duty ratio which is the same as or different from the input duty ratio, and control the driving current to be on and off based on the output dimming pulse.

Abstract: 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.

Abstract: 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.

Abstract: A control circuit of a driving circuit for supplying a driving current to a light source includes: a pulse width modulation (PWM) input terminal configured to receive an input dimming pulse having an input duty ratio corresponding to a target light quantity of the light source, the input dimming pulse being pulse-width modulated; and a dimming controller configured to convert a period and a pulse width of the input dimming pulse into digital values, reconvert the digital values into an output dimming pulse having an output duty ratio which is the same as or different from the input duty ratio, and control the driving current to be on and off based on the output dimming pulse.

Abstract: A current drive circuit capable of reducing the influence of temperature variation or individual deviation is provided. An output transistor is a PNP bipolar transistor, and has an emitter connected to a cathode of an LED string. A current control resistor is disposed between a collector of the output transistor and a ground terminal. An output terminal of an error amplifier is connected to a base of the output transistor, a first input terminal of the error amplifier is connected to a connection point of the output transistor and the current control resistor, and a reference voltage is applied to a second input terminal of the error amplifier. The error amplifier enables a sink current sunk from the output terminal to flow to the current control resistor.

Abstract: An error amplifier amplifies the difference between a first detection voltage VR at a first detection resistor on a path of a driving current ILED and a dimming control signal VDIM that corresponds to the target luminance level of a light emitting element. A pulse width modulator generates a gate pulse signal according to an output VFB of the error amplifier. M comparators each assert an overcurrent detection signal when a corresponding detection voltages VR1 or VR2 that corresponds to voltage drop across detection resistors R1 or R2 exceeds a corresponding threshold voltage VTH1 or VTH2. Of the threshold voltages VTH1 and VTH2, at least one is set (i) to increase as the dimming control signal VDIM increases when the dimming control signal VDIM exceeds a predetermined first value, and (ii) to a predetermined lower limit value when the dimming control signal VDIM is lower than the first value.

Abstract: A positive counter starts counting, starting with an initial value, upon receiving a positive edge of a dimming pulse signal. A negative edge counter starts counting, starting with an initial value, upon receiving a negative edge of the dimming pulse signal. For each i-th (2?i?n) channel, the phase shift amount is calculated by multiplying a period count value that indicates the period of the dimming pulse signal by (i?1)/n. When the count value matches the phase shift amount, a burst control signal is switched to a first level. When the count value matches the phase shift amount, the burst control signal is switched to a second level.

Abstract: A pulse width modulated dimming pulse signal PWM is input to a control input terminal P5. A standby terminal P6 receives a standby signal STB that indicates switching between a standby state and an operating state of a current drive circuit 8. A burst dimming terminal BS is provided to each of eight respective channels. Each burst dimming terminal BS receives a voltage at one terminal (cathode) of a corresponding LED string 6. When the voltage level of the standby signal STB is included in a first voltage range, a burst controller 9 is set to an all channel common mode, and when it is included in a second voltage range, the mode is set to a phase shift mode ?SHIFT. The burst controller 9 set to the phase shift mode ?SHIFT automatically sets the phase shift angle according to the number of connected LED strings 6.

Abstract: A current drive circuit capable of reducing the influence of temperature variation or individual deviation is provided. An output transistor is a PNP bipolar transistor, and has an emitter connected to a cathode of an LED string. A current control resistor is disposed between a collector of the output transistor and a ground terminal. An output terminal of an error amplifier is connected to a base of the output transistor, a first input terminal of the error amplifier is connected to a connection point of the output transistor and the current control resistor, and a reference voltage is applied to a second input terminal of the error amplifier. The error amplifier enables a sink current sunk from the output terminal to flow to the current control resistor.

Abstract: A positive counter starts counting, starting with an initial value, upon receiving a positive edge of a dimming pulse signal. A negative edge counter starts counting, starting with an initial value, upon receiving a negative edge of the dimming pulse signal. For each i-th (2?i?n) channel, the phase shift amount is calculated by multiplying a period count value that indicates the period of the dimming pulse signal by (i?1)/n. When the count value matches the phase shift amount, a burst control signal is switched to a first level. When the count value matches the phase shift amount, the burst control signal is switched to a second level.

Abstract: A pulse width modulated dimming pulse signal PWM is input to a control input terminal P5. A standby terminal P6 receives a standby signal STB that indicates switching between a standby state and an operating state of a current drive circuit 8. A burst dimming terminal BS is provided to each of eight respective channels. Each burst dimming terminal BS receives a voltage at one terminal (cathode) of a corresponding LED string 6. When the voltage level of the standby signal STB is included in a first voltage range, a burst controller 9 is set to an all channel common mode, and when it is included in a second voltage range, the mode is set to a phase shift mode ?SHIFT. The burst controller 9 set to the phase shift mode ?SHIFT automatically sets the phase shift angle according to the number of connected LED strings 6.