Disabling arrangement for a circuit operating at a deflection rate

• US 5,017,844 A
• Filed: 04/30/1990
• Issued: 05/21/1991
• Est. Priority Date: 04/30/1990
• Status: Expired due to Term

• Current Assignee: RCA Licensing Corporation
• Original Assignee: RCA Licensing Corporation
• Inventors: Lendaro, Jeffery B.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/516,384
• Time in Patent Office: 386 Days
• Field of Search: 315/408, 315/411, 315/399, 358/190, 358/194.1
• US Class Current: 315/408
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H04N 3/20 Prevention of damage to cathode-ray tubes in the event of failure of scanning
• CPC Class Codes: H04N 5/63 Generation or supply of power specially adapted for television receivers
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Active turn-off or disabling circuits respond to control signals from a control unit which defines the mode of operation of a receiver. In response to a designation of a standby mode of operation the active disabling unit actively disables a pulse width modulator to prevent pulses from being produced based upon an input of ringing signal. In addition, the active disabling circuits prevent such ringing signal from negatively effecting pincusion protection circuits. The ringing signal is produced in a horizontal flyback transformer during a transition interval that follows a transition to standby mode of operation.

Claims

1. A video display apparatus, comprising:

a source of an on/off control signals that is indicative when operation in a standby mode is required and when operation in a run mode is required;

a horizontal deflection circuit output stage responsive to said on/off control signal for generating a second control signal having signal transitions during said run mode and during a first interval that follows a change in said on/off control signal to said standby mode of operation such that, during said standby mode operation following said first interval, the signal transitions in said second control signal cease;

a source of modulation signal; and

an East-West raster distortion modulator responsive to said modulation signal, having first and second terminals coupled to receive said on/off and second control signals, respectively, and having an output terminal coupled to a control terminal of a transistor for producing a pulse-width modulated switching operation in said transistor during said run mode operation that modulates a deflection current in an East-West manner such that, during said transition interval, the switching operation in said transistor is disabled via said first terminal by the operation of said on/off control signals, and such that during said standby mode operation following said first interval, the switching operation is disabled via at least said second terminal by the operation of said second control signal.

2. A video display apparatus, comprising:

a source of an on/off control signal that is indicative when operation in a standby mode is required and when operation in a run mode is required;

a deflection circuit output stage responsive to said on/off control signal for generating a second control signal having signal transitions during said run mode and during a first interval that follows a change in said on/off control signal to said standby mode of operation such that, during said standby mode operation following said first interval, the signal transitions in said second control signal cease;

a source of a third control signal at a frequency that is related to a deflection frequency; and

a pulse-width modulator responsive to said control signal, having first and second terminals coupled to receive said on/off and second control signals, respectively, and having an output terminal coupled to a control terminal of a transistor for producing a pulse-width modulated switching operation in said transistor during said run mode operation that controls a deflection current amplitude in accordance with said control signal such that, during said transition interval, the switching operation in said transistor is disabled via said first terminal by the operation of said on/off control signal, and such that during said standby mode operation following said first interval, the switching operation is disabled via at least at said second terminal by the operation of said second control signal.

3. A video display apparatus, comprising:

a source of an on/off control signal that is indicative when operation in a standby mode is required and when operation in a run mode is required;

a deflection circuit output stage;

a first on/off switch coupled to said output stage and responsive to said on/off control signal for enabling operation of said output stage during said run mode and for disabling operation thereof during said standby mode operation;

a source of modulation signal;

a second on/off switch responsive to said on/off control signal, said second on/off switch having a first switching state during said standby mode and a second switching state during said run mode; and

an East-West raster distortion modulator stage coupled to said second on/off switch and to said modulation signal source, said modulator being enabled by said second on/off switch during said run mode to provides East-West deflection current modulation, said modulator stage being actively disabled by said second on/off switch when said standby mode is asserted.

4. A video display apparatus, comprising:

a source of an on/off control signal that is indicative when operation in a standby mode is required and when operation in a run mode is required;

a deflection circuit output stage;

a first on/off switch coupled to said output stage and responsive to said on/off control signal for enabling operation of said stage during said run mode and for disabling operation thereof during said standby mode operation;

a source of a second control signal at a frequency related to a deflection frequency;

a second on/off switch responsive to said on/off control signal, said second on/off switch having a first switching state during said standby mode and a second switching stage during said run mode; and

means coupled to said second on/off switch and to said second control signal source for varying a deflection current in said output stage in accordance with said second control signal during said run mode, said deflection current varying means being actively disabled by said second on/off switch when said standby mode is asserted.