US 2012/0056552 A1Published application

Multi-mode dimming circuit

AssigneeChengdu Monolithic Power Systems Co., Ltd.

InventorsBo Yu, Yuancheng Ren, Lei Du, Naixing Kuang, Zhijiang Yang

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Abstract

The present disclosure discloses a multi-mode dimming circuit configurable to operate in a first dimming mode, a second dimming mode and a third dimming mode. The present disclosure also discloses separate dimming circuits for respectively realize the three dimming modes. In one embodiment the multi-mode dimming circuit may comprise a first input terminal, a second input terminal, a third input terminal, an output terminal, a resistive device, an oscillation circuit and a pulse width modulation (PWM) circuit. Users may flexibly configure the multi-mode dimming circuit to operate in one of the three different dimming modes by varying the external devices and/or signals coupled to each of the first, second and third input terminals.

Claims17

Dependent claims

A multi-mode dimming circuit configurable to operate in a first dimming mode, a second dimming mode or a third dimming mode, comprising:

a first input terminal;
a second input terminal;
a third input terminal;
an output terminal;
a first resistive device having a first terminal coupled to the first input terminal, and a second terminal coupled to the second input terminal;
an oscillation circuit having an oscillation input terminal coupled to the third input terminal, and an oscillation output terminal configured to provide an oscillation output signal;
and
a PWM circuit having a first PWM input terminal coupled to the second input terminal, a second PWM input terminal coupled to the oscillation output terminal, and a PWM output terminal coupled to the output terminal, wherein the PWM circuit is configured to compare a signal at the first PWM input terminal with the oscillation output signal to generate a PWM dimming signal having a first duty cycle and a first frequency;
and wherein
the multi-mode dimming circuit operates in the first dimming mode when the first input terminal is configured to receive a PWM input signal having a second duty cycle and a second frequency, the second input terminal is coupled to a first capacitive device, and the third input terminal is coupled to a second capacitive device such that the oscillation output signal comprises a first triangle signal;
and wherein
the multi-mode dimming circuit operates in the second dimming mode when the first input terminal is configured to receive the PWM input signal, the second input terminal is idled, and the third input terminal is coupled to a second resistive device such that the oscillation output signal comprises a DC reference signal;
and wherein
the multi-mode dimming circuit operates in the third dimming mode when the first input terminal is idled, the second input terminal is configured to receive a DC analog signal, and the third input terminal is coupled to a third capacitive device such that the oscillation output signal comprises a second triangle signal.

11 more elements

A dimming circuit comprising:

a first input terminal configured to receive a PWM input signal having a first duty cycle and a first frequency;
a second input terminal;
a third input terminal;
an output terminal configured to provide a PWM dimming signal having a second duty cycle and a second frequency;
a first resistive device having a first terminal coupled to the first input terminal, and a second terminal coupled to the second input terminal;
a first capacitive device having a first terminal coupled to the second input terminal, and a second terminal connected to ground;
a second capacitive device having a first terminal coupled to the third input terminal, and a second terminal connected to ground;
an oscillation circuit having an oscillation input terminal coupled to the third input terminal, and an oscillation output terminal configured to provide an oscillation output signal;
and
a PWM circuit having a first PWM input terminal coupled to the second input terminal, a second PWM input terminal coupled to the oscillation output terminal, and a PWM output terminal coupled to the output terminal, wherein the PWM circuit is configured to compare a signal at the first PWM input terminal with the oscillation output signal to generate the PWM dimming signal.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/224,893Filed 2 Sep 2011
Priority: CN 201010276366.33 Sep 2010
Published: 8 Mar 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H05B 41/3927
With possibility of light intensity variations: by pulse width modulation
H05B 45/10
Circuit arrangements for operating light-emitting diodes [LED]: controlling the intensity of the light
Y02B 20/30
Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps: semiconductor lamps, e.g. solid state lamps [SSL] light…
H05B
Electric heating