Power saving regulated light emitting diode circuit

Patent · Tue Mar 12 04:00:00 EST 1985

OSTI ID:5486498

Haville, G D

A power saving regulated light source circuit, comprising a light emitting diode (LED), a direct current source and a switching transistor connected in series with the LED, a control voltage producing resistor connected in series with the LED to produce a control voltage corresponding to the current through the LED, a storage capacitor connected in parallel with the series combination of the LED and the resistor, a comparator having its output connected to the input of the transistor, the comparator having a reference input and a control input, a stabilized biasing source for supplying a stabilized reference voltage to the reference input, the control input of the comparator being connected to the control voltage producing resistor, the comparator having a high output state when the reference voltage exceeds the control voltage while having a low output state when the control voltage exceeds the reference voltage, the transistor being conductive in response to the high state while being nonconductive in response to the low state, the transistor when conductive being effective to charge the capacitor and to increase the control voltage, whereby the comparator is cycled between the high and low output states while the transistor is cycled between conductive and nonconductive states.

• Assignee: BEI Electronics, Inc.
• Patent Number(s): US 4504776
• OSTI ID: 5486498
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
CAPACITORS
COMPARATOR CIRCUITS
CURRENTS
DIRECT CURRENT
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTRONIC CIRCUITS
EQUIPMENT
LIGHT EMITTING DIODES
RESISTORS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SWITCHING CIRCUITS
TRANSISTOR SWITCHING CIRCUITS
VOLTAGE REGULATORS