摘要:
A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.
摘要:
A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.
摘要:
A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.
摘要:
A dimming method for LED driving circuit is proposed. By temporary switching a pin that is originally used for the input/output of other electric signals to a high impedance node, the dimming control signal may be inputted to dim LEDs. The dimming method comprises the steps of: floating the pin every a period of time to pull the pin's voltage being equal to the dimming control signal; detecting the pin's voltage; and retrieving the dimming control signal in accordance with the detected pin's voltage and thereafter dimming the LEDs.
摘要:
For efficiency improvement of a LED display system including a charge pump and a LED connected to either the voltage input terminal or the voltage output terminal of the charge pump, either one or both of two current regulators are enabled according to a voltage detected from the LED, for establishing a driving current for the LED. When the detected voltage is higher than a threshold, the first one of the current sources is enabled sole. When the detected voltage is lower than the threshold, the second one of the current sources is enabled sole, or both the current sources are enabled, or the current sources are alternatively enabled.
摘要:
The present invention provides a transistor switch on a light emitting device channel, the transistor switch receiving a control voltage VG. A current source circuit controls the current on the light emitting device channel, the current source circuit requiring a minimum voltage VR for normal operation. The present invention further provides a dynamic headroom controller circuit which compares a voltage VS at a current outflow end of the transistor switch with the voltage VR to determine the relationship between the voltage VS and the voltage VR when the control voltage VG is higher than a reference voltage VH, and adjusts the voltage difference between the voltage VS and the voltage VR accordingly.
摘要:
A single-ended operational amplifier includes an output stage, a first transconductance amplifier and a second transconductance amplifier. In an offset cancellation mode, two inputs of the first transconductance amplifier are supplied with a reference voltage to sink two currents from two inputs of the output stage respectively, the output stage generates a third current according to the difference between the two currents to charge a capacitor, and the second transconductance amplifier generates two currents according to the voltage in the capacitor to make currents in the two inputs of the output stage equal to each other, thereby canceling the offset of the single-ended operational amplifier.
摘要:
A low noise multiphase charge pump comprises a plurality of capacitors and a plurality of switches configured as a network, the switches are so switched that the charge pump operates in at least three phases by turns, and the operational durations and the operational currents of the phases are preferably balanced, so as to reduce the noise of the charge pump.
摘要:
A low noise multiphase charge pump comprises a plurality of capacitors and a plurality of switches configured as a network, the switches are so switched that the charge pump operates in at least three phases by turns, and the operational durations and the operational currents of the phases are preferably balanced, so as to reduce the noise of the charge pump.
摘要:
A charge pump regulator has a charge pump to establish a charge path and a discharge path alternately, so as to produce a regulated voltage on an output terminal. The charge pump has at least a current control element on the charge path or the discharge path to control the current flowing therethrough according to an output-dependent feedback signal.