摘要:
An electronic circuit includes circuit portions for identifying a largest voltage drop through one of a plurality of series connected diode strings and for controlling a boost switching regulator according to the largest voltage drop. The electronic circuit can sense an open circuit series connected diode string, which would otherwise have the largest voltage drop, and can disconnect that open circuit series connected diode string from control of the boost switching regulator. Another electronic circuit includes a current limiting circuit coupled to or within a boost switching regulator and configured to operate with a diode load. Another electronic circuit includes a pulse width modulation circuit configured to dim a series connected string of light emitting diodes.
摘要:
An electronic circuit includes circuit portions for identifying a largest voltage drop through one of a plurality of series connected diode strings and for controlling a boost switching regulator according to the largest voltage drop. The electronic circuit can sense an open circuit series connected diode string, which would otherwise have the largest voltage drop, and can disconnect that open circuit series connected diode string from control of the boost switching regulator. Another electronic circuit includes a current limiting circuit coupled to or within a boost switching regulator and configured to operate with a diode load. Another electronic circuit includes a pulse width modulation circuit configured to dim a series connected string of light emitting diodes.
摘要:
An electronic circuit includes circuit portions for identifying a largest voltage drop through one of a plurality of series connected diode strings and for controlling a boost switching regulator according to the largest voltage drop. The electronic circuit can sense an open circuit series connected diode string, which would otherwise have the largest voltage drop, and can disconnect that open circuit series connected diode string from control of the boost switching regulator. Another electronic circuit includes a current limiting circuit coupled to or within a boost switching regulator and configured to operate with a diode load. Another electronic circuit includes a pulse width modulation circuit configured to dim a series connected string of light emitting diodes.
摘要:
An electronic circuit includes circuit portions for identifying a largest voltage drop through one of a plurality of series connected diode strings and for controlling a boost switching regulator according to the largest voltage drop. The electronic circuit can sense an open circuit series connected diode string, which would otherwise have the largest voltage drop, and can disconnect that open circuit series connected diode string from control of the boost switching regulator. Another electronic circuit includes a current limiting circuit coupled to or within a boost switching regulator and configured to operate with a diode load. Another electronic circuit includes a pulse width modulation circuit configured to dim a series connected string of light emitting diodes.
摘要:
A capacitor charging circuit is provided with a primary side output voltage sensing circuit for generating a control signal indicative of whether the output voltage has reached a desired level. The control signal is unaffected by voltage spikes occurring when the main switch is turned off. In one embodiment, the circuit filters the primary side voltage for comparison to a reference voltage in order to provide the control signal. In another embodiment, an AND gate provides the control signal indicating that the output voltage has reached the desired level only in response to the primary side voltage being greater than a reference voltage and the secondary current being discontinuous. In a further embodiment, an AND gate provides the control signal indicating that the output voltage has reached the desired levels only in response to a predetermined delay occurring after the primary side voltage becomes greater than a reference voltage and the secondary current being discontinuous. According to a further aspect of the invention, an auxiliary switch is provided to reduce the reverse recovery time of the output diode in order to speed up the capacitor charging time.
摘要:
In one aspect, a circuit includes a plurality of comparators. Each comparator is configured to receive a first input from a corresponding load of a plurality of loads and to receive a second input as a regulation voltage. The circuit also includes an amplifier configured to receive signals provided by the plurality of comparators, a pulse-width modulation (PWM) circuit configured to receive a control signal from the amplifier and to provide a signal to a primary switch to control voltage provided to the loads and an output switch sequencer coupled to each of the comparators and configured to provide control signals to control switches coupled to the primary switch enabling one control switch to be active at a time. Each control switch provides a voltage increase to a respective load of the plurality of loads if enabled.
摘要:
Electronic circuits provide an error signal to control a regulated output voltage signal generated by a controllable DC-DC converter for driving one or more series connected strings of light emitting diodes.
摘要:
Circuits and methods used therein provide an adjustable average current through a load in accordance with a pulse width modulated (PWM) signal. A condition detection circuit is configured to identify a condition of the electronic circuit and to generate a condition signal indicative of the condition. A current extension circuit is coupled receive the condition signal and coupled to receive the PWM signal. The current extension circuit is configured to generate, at the output node of the current extension circuit, an extended PWM signal having a first state and a second state. The first state of the extended PWM signal longer in time than a first state of the PWM signal by an amount related to a value or a state of the condition signal. Current pulses through the load are extended to be longer in accordance with the extended PWM signal.
摘要:
In one aspect, a circuit includes a plurality of comparators. Each comparator is configured to receive a first input from a corresponding load of a plurality of loads and to receive a second input as a regulation voltage. The circuit also includes an amplifier configured to receive signals provided by the plurality of comparators, a pulse-width modulation (PWM) circuit configured to receive a control signal from the amplifier and to provide a signal to a primary switch to control voltage provided to the loads and an output switch sequencer coupled to each of the comparators and configured to provide control signals to control switches coupled to the primary switch enabling one control switch to be active at a time. Each control switch provides a voltage increase to a respective load of the plurality of loads if enabled.
摘要:
Electronic circuits provide an error signal to control a regulated output voltage signal generated by a controllable DC-DC converter for driving one or more series connected strings of light emitting diodes.