Magnetic deflection sweep amplifier with intelligent flyback
AssigneeSquibb Vitatek Inc.
InventorRichard A. Sunderland
Life of this patent
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Abstract
The magnetic deflection sweep amplifier includes a first switch, such as a MOSFET in series with a deflection yoke. The switch is controlled by a second switch, such as a bipolar transistor, and the second switch is able to selectively control the first switch, whereby the yoke current can be reversed, to provide complete flyback, or can be truncated part way through flyback to stop the retrace at an intermediate position. The flyback amplifier also has provision for linear operation without flyback. The present invention accomplishes the foregoing with very few parts and with very little power consumption.
Claims9
A magnetic deflection circuit for a CRT display comprising:
- (a) an amplifier having an input and an output;
- (b) an inductive yoke which receives at one terminal an input signal from the output of said amplifier;
- (c) a capacitor connected to the other terminal of said yoke, the other side of said capacitor being connected to means for returning the output signal to said input of said amplifier;
- (d) means for sensing the current flow through said yoke;
- (e) switch means for selectively shorting said capacitor, said switch means having a low resistance state and a high resistance state;
- and
- (f) a diode connected across said switch means, said diode permitting unidirectional current flow when said switch means is in its high resistance state;
- and
- (g) control means for selectively controlling said switch means in response to the output voltage of said amplifier, said control means placing said switch means into its high resistance state when the desired yoke current has a value, relative to the actual yoke current, such that said diode does not permit current flow.
Dependencies are inferred from the claim text.