Light emission control device, light source device, and projection type video display device
AssigneeSeiko Epson Corporation
InventorKei ISHIMARU
Life of this patent
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Abstract
The light emission control device includes a PWM terminal to which a PWM signal is input, a first drive circuit for outputting a first control signal, a second drive circuit for outputting a second control signal, and a mode judgment circuit. The first control signal sets the first switching element to an ON state when the PWM signal is in an active state, and sets the first switching element to an OFF state when the PWM signal is in an inactive state. The second control signal controls an ON/OFF state of the second switching element when the PWM signal is in the active state. The mode judgment circuit judges between a PWM dimming mode and an analog dimming mode based on the PWM signal.
Claims15
Alight emission control device configured to control a first switching element disposed in series to a light emitting element between a first power supply node and one end of an inductor, and a second switching element disposed between another end of the inductor and a second power supply node, the light emission control device comprising:
- a PWM terminal to which a PWM signal is input;
- a first drive circuit configured to output a first control signal for setting the first switching element to an ON state when the PWM signal is in an active state, and setting the first switching element to an OFF state when the PWM signal is in an inactive state;
- a second drive circuit configured to output a second control signal for controlling an ON/OFF state of the second switching element when the PWM signal is in the active state;
- and
- a mode judgment circuit configured to judge between a PWM dimming mode as a dimming mode using the first control signal, and an analog dimming mode as a dimming mode using the second control signal based on the PWM signal.
A light source device comprising:
- a light emitting element electrically coupled between a first power supply node and a first node;
- a first switching element electrically coupled in series to the light emitting element between the first power supply node and the first node;
- an inductor electrically coupled between the first node and a second node;
- a second switching element electrically coupled between the second node and a second power supply node;
- and
- a light emission control device configured to output a first control signal to the first switching element, and output a second control signal to the second switching element, wherein
- the light emission control device includes
- a PWM terminal to which a PWM signal is input,
- a first drive circuit configured to output the first control signal for setting the first switching element to an ON state when the PWM signal is in an active state, and setting the first switching element to an OFF state when the PWM signal is in an inactive state,
- a second drive circuit configured to output the second control signal for controlling an ON/OFF state of the second switching element in a period in which the PWM signal is in the active state, and
- a mode judgment circuit configured to judge between a PWM dimming mode as a dimming mode using the first control signal, and an analog dimming mode as a dimming mode using the second control signal based on the PWM signal.
Dependencies are inferred from the claim text.