Plasma television and power supply circuit
First Claim
1. Plasma television having a sustain voltage generator initiating an oscillation on a primary side of the sustain voltage generator upon inputting thereto of a startup signal and taking a predetermined time until a sustain voltage from a secondary side of the sustain voltage generator becomes an ordinary voltage after the oscillation is started, for displaying on a screen a video image based on a video signal input thereto, comprising:
- a rectifier circuit supplied with an AC voltage for generating a DC voltage;
an address voltage generator having the DC voltage input to a primary address winding of a transformer and generating an address voltage in a secondary address winding for outputting the address voltage to a plasma display panel;
the sustain voltage generator having the DC voltage input to a primary sustain winding of a transformer and generating the sustain voltage and a monitor voltage, that are out put through conductors located in different tap positions of a secondary sustain winding and different in voltage level, for outputting the sustain voltage to the plasma display panel and the monitor voltage to outside;
a stand-by voltage generator having the DC voltage input to a primary stand-by winding of a transformer for generating a first erase voltage, a second erase voltage, and a scan voltage, that are output from conductors located in different tap positions of a secondary stand-by winding and being different in voltage level, for outputting the stand-by voltages to the plasma display panel;
a detector circuit including first voltage dividing resistors having first end supplied with the monitor voltage, a dividing point generating an inspection voltage and second end grounded;
a relay circuit for switching between turning ON and OFF of the AC voltage to the rectifier circuit;
a microcomputer for instructing the relay circuit to switch to turning OFF the AC voltage to the rectifier circuit when the inspection voltage input at an Analog/Digital (A/D) terminal is lower than a predetermined voltage; and
a detection invalidating circuit configured to comprise;
second voltage dividing resistors having first end supplied with an externally supplied constant voltage equal to or above a predetermined voltage, a dividing point connected to the A/D terminal of the microcomputer and second end grounded;
third voltage dividing resistors having first end grounded;
a zener diode having an anode connected with second end of the third voltage dividing resistors and a cathode supplied with the sustain voltage, the zener diode broken down under the sustain voltage after elapse of a predetermined time from the start of the oscillation; and
a transistor having a collector connected with a voltage dividing point of the second voltage dividing resistors, a base connected with a voltage dividing point of the third voltage dividing resistors, and an emitter grounded.
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Accused Products
Abstract
The present invention discloses a power supply circuit initiating an oscillation on a primary side of the power supply circuit upon receipt of a startup signal, comprising: a detecting module receiving an output voltage from the power supply circuit for detecting whether the output voltage is below a predetermined voltage; a power supply switching module turning OFF a main power supply of the power supply circuit when the detecting module determines the output voltage to be below the predetermined voltage; and a detection invalidating module invalidating the detecting of the detecting module from the receipt of the predetermined startup signal to the output voltage becomes above or equal the predetermined voltage.
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Citations
3 Claims
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1. Plasma television having a sustain voltage generator initiating an oscillation on a primary side of the sustain voltage generator upon inputting thereto of a startup signal and taking a predetermined time until a sustain voltage from a secondary side of the sustain voltage generator becomes an ordinary voltage after the oscillation is started, for displaying on a screen a video image based on a video signal input thereto, comprising:
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a rectifier circuit supplied with an AC voltage for generating a DC voltage; an address voltage generator having the DC voltage input to a primary address winding of a transformer and generating an address voltage in a secondary address winding for outputting the address voltage to a plasma display panel; the sustain voltage generator having the DC voltage input to a primary sustain winding of a transformer and generating the sustain voltage and a monitor voltage, that are out put through conductors located in different tap positions of a secondary sustain winding and different in voltage level, for outputting the sustain voltage to the plasma display panel and the monitor voltage to outside; a stand-by voltage generator having the DC voltage input to a primary stand-by winding of a transformer for generating a first erase voltage, a second erase voltage, and a scan voltage, that are output from conductors located in different tap positions of a secondary stand-by winding and being different in voltage level, for outputting the stand-by voltages to the plasma display panel; a detector circuit including first voltage dividing resistors having first end supplied with the monitor voltage, a dividing point generating an inspection voltage and second end grounded; a relay circuit for switching between turning ON and OFF of the AC voltage to the rectifier circuit; a microcomputer for instructing the relay circuit to switch to turning OFF the AC voltage to the rectifier circuit when the inspection voltage input at an Analog/Digital (A/D) terminal is lower than a predetermined voltage; and a detection invalidating circuit configured to comprise;
second voltage dividing resistors having first end supplied with an externally supplied constant voltage equal to or above a predetermined voltage, a dividing point connected to the A/D terminal of the microcomputer and second end grounded;
third voltage dividing resistors having first end grounded;
a zener diode having an anode connected with second end of the third voltage dividing resistors and a cathode supplied with the sustain voltage, the zener diode broken down under the sustain voltage after elapse of a predetermined time from the start of the oscillation; and
a transistor having a collector connected with a voltage dividing point of the second voltage dividing resistors, a base connected with a voltage dividing point of the third voltage dividing resistors, and an emitter grounded.
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2. A power supply circuit initiating an oscillation on a primary side of the power supply circuit upon receipt of a startup signal, comprising:
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a detecting module receiving an output voltage from the power supply circuit for detecting whether the output voltage is below a predetermined voltage; a power supply switching module turning OFF a main power supply of the power supply circuit when the detecting module determines the output voltage to be below the predetermined voltage; and a detection invalidating module invalidating the detecting of the detecting module from the receipt of the predetermined startup signal to the output voltage becomes above or equal the predetermined voltage. - View Dependent Claims (3)
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Specification