Abstract:
The present invention relates to a current-balance circuit and a backlight module having the same. The current balance circuit includes a current balance unit, a control unit, and a detection unit. The current balance unit is connected to a plurality of light units to regulate the current of the plurality of light units, independent from the effects of input voltage. The detection unit is connected to the plurality of light units and the current balance unit to detect the minimum operating voltage for the plurality of light units. The control unit, connected to the current balance unit, controls the operation of the plurality of light units.
Abstract:
A light emitting diode (LED) driving apparatus is disclosed. The LED driving apparatus includes a power converter, a voltage sample-and-hold and comparison circuit, and a pre-charge clock generator. The power converter has a power transistor switch for processing power conversion and outputs a driving voltage at an output terminal. The voltage sample-and-hold and comparison circuit enters a sample-and-hold mode or a comparing mode according to a dimming status signal. The voltage sample-and-hold and comparison circuit samples and holds a feedback voltage to obtain a pre-storage voltage during the sample-and-hold mode and compares the pre-storage voltage with the feedback voltage to obtain a comparison result during the comparing mode. The voltage sample-and-hold and comparison circuit generates a pre-charge enable signal according to the comparison result. The pre-charge clock generator generates a pre-charge clock signal to control the power transistor switch according to the pre-charge enable signal and a clock signal.
Abstract:
An LED driving module suitable to drive a plurality of LED strings in parallel connection is disclosed. The LED driving module includes a voltage converting apparatus, a conduction voltage detecting apparatus, a reference voltage generating apparatus and a current-adjusting apparatus. The voltage converting apparatus produces a driving voltage according to a conduction voltage. The conduction voltage detecting apparatus detects the conducting states of the LED strings for producing a conduction voltage and an enabling signal. The reference voltage generating apparatus generates a first reference voltage according to the enabling signal. The current-adjusting apparatus produces a plurality of driving currents according to the first reference voltage, and the driving currents flow through the LED strings.
Abstract:
An ultrasonic transducer comprising a flexible membrane, a first electrode in the flexible membrane, a second electrode in the flexible membrane, and a chamber in the flexible membrane between the first electrode and the second electrode.
Abstract:
The present invention relates to a current-balance circuit and a backlight module having the same. The current balance circuit includes a current balance unit, a control unit, and a detection unit. The current balance unit is connected to a plurality of light units to regulate the current of the plurality of light units, independent from the effects of input voltage. The detection unit is connected to the plurality of light units and the current balance unit to detect the minimum operating voltage for the plurality of light units. The control unit, connected to the current balance unit, controls the operation of the plurality of light units.
Abstract:
An LED driving module suitable to drive a plurality of LED strings in parallel connection is disclosed. The LED driving module includes a voltage converting apparatus, a conduction voltage detecting apparatus, a reference voltage generating apparatus and a current-adjusting apparatus. The voltage converting apparatus produces a driving voltage according to a conduction voltage. The conduction voltage detecting apparatus detects the conducting states of the LED strings for producing a conduction voltage and an enabling signal. The reference voltage generating apparatus generates a first reference voltage according to the enabling signal. The current-adjusting apparatus produces a plurality of driving currents according to the first reference voltage, and the driving currents flow through the LED strings.
Abstract:
A light emitting diode (LED) driving apparatus is disclosed. The LED driving apparatus includes a power converter, a voltage sample-and-hold and comparison circuit, and a pre-charge clock generator. The power converter has a power transistor switch for processing power conversion and outputs a driving voltage at an output terminal. The voltage sample-and-hold and comparison circuit enters a sample-and-hold mode or a comparing mode according to a dimming status signal. The voltage sample-and-hold and comparison circuit samples and holds a feedback voltage to obtain a pre-storage voltage during the sample-and-hold mode and compares the pre-storage voltage with the feedback voltage to obtain a comparison result during the comparing mode. The voltage sample-and-hold and comparison circuit generates a pre-charge enable signal according to the comparison result. The pre-charge clock generator generates a pre-charge clock signal to control the power transistor switch according to the pre-charge enable signal and a clock signal.