Dimmable instant-start ballast
AssigneeDelta Electronics, Inc.
InventorsChing-Ho CHOU, Yung-Chuan LU
Life of this patent
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Abstract
A dimmable instant-start ballast for a plurality of LED lamps and/or a plurality of fluorescent lamps is provided, which includes an isolated dimming interface, a duty control device, a dimming switch, and an inverter circuit. The isolated dimming interface receives a dimming signal to generate a dimming voltage. The duty control device generates an operation signal according to the dimming voltage. The dimming switch periodically couples a first node to a ground according to the operation signal. The inverter circuit receives a rectified voltage and is coupled to the first node. When the first node is coupled to the ground terminal, the inverter circuit provides a lamp current for the LED lamps and/or the fluorescent lamps.
Claims15
A dimmable instant-start ballast for a plurality of LED lamps and/or a plurality of fluorescent lamps, comprising:
- an isolated dimming interface, receiving a dimming signal to generate a dimming voltage;
- a duty control device, generating an operation signal according to the dimming voltage;
- a dimming switch, periodically coupling a first node to a ground terminal according to the operation signal;
- and
- an inverter circuit, receiving a rectified voltage and coupled to the first node, wherein the inverter circuit generates a lamp current to the LED lamps and/or the fluorescent lamps when the first node is coupled to the ground terminal, wherein the dimming switch periodically operates in an conductive state and an non-conductive state according to a duty cycle of the operation signal, wherein the first node is coupled to the ground terminal and the inverter circuit generates the lamp current when the dimming switch operates in the conductive state, wherein the first node is not coupled to the ground terminal and the inverter circuit does not generate the lamp current when the dimming switch operates in the non-conductive state, wherein the lamp current flows through the LED lamps and/or the fluorescent lamps to generate an illumination brightness, and wherein the illumination brightness is proportional to the duty cycle.
(canceled)
A dimmable control device for controlling an inverter circuit to periodically generate a lamp current to a plurality of LED lamps and/or a plurality of fluorescent lamps, comprising:
- an isolated dimming interface, receiving a dimming signal to generate a dimming voltage;
- a voltage regulator, generating a DC supply voltage;
- a duty control signal generator, receiving the DC supply voltage, comprising:
- a triangle-wave generating circuit, generating a triangle-wave signal;
- a clamp circuit, rectifying the dimming voltage to a DC dimming voltage and providing a maximal one between the DC dimming voltage and a reference voltage for a comparison node;
- and
- a comparator, comparing a voltage of the comparison node with the triangle-wave signal to generate a duty control signal;
- a switch-driving circuit, receiving the DC supply voltage and generating an operation signal according to the duty control signal;
- and
- a dimming switch, periodically turning ON, according to the operation signal, to couple the inverter circuit to the ground terminal, such that the inverter circuit periodically generates the lamp current.
Dependencies are inferred from the claim text.