Television vertical ramp generator
AssigneeRCA Corporation
InventorAdel A. A. Ahmed
Life of this patent
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Abstract
A vertical sawtooth generator adaptable for integrated circuit application self-oscillates under control of a latch circuit. A circuit controls the linearity of the charging capacitor ramp voltage. High frequency components of the recurrent ramp occurring due to the retrace discharge current are reduced by controlling the discharge currents. The ramp rate is controlled by a single resistor external to an integrated circuit.
Claims1
A ramp generator for use with a ramp voltage utilization means, said ramp generator incorporating an integrated circuit having interface terminals for coupling circuitry disposed on said integrated circuit with circuitry external to said integrated circuit, said ramp generator comprising:
- a first capacitance means disposed external to said integrated circuit having a first electrode coupled to a point of reference potential;
- second capacitance means disposed external to said integrated circuit having a first electrode coupled to a second electrode of said first capacitance means at a juncture, and having a second electrode;
- a source of potential defined between a point of supply potential and said point of reference potential;
- first resistance means disposed external to said integrated circuit and coupled to said point of supply potential and to said second electrode of said second capacitance means for forming a ramp voltage across said capacitance means;
- first emitter follower means formed on said integrated circuit and having an input coupled to said second electrode of said second capacitance means via one of said interface terminals and having an output electrode;
- ramp voltage reponsive means, disposed on said integrated circuit, and having an input coupled to said output electrode of said first emitter follower means and an output coupled to said one interface terminal, for controlling the termination of said ramp voltage formation;
- voltage division means formed on said integrated circuit and coupled to said output electrode of said first emitter follower means and to said point of supply potential and having a tap at which appears an attenuated version of said ramp voltage;
- second emitter follower means formed on said integrated circuit and having an input electrode coupled to said tap and having an output electrode coupled to said ramp voltage utilization means via another of said interface terminals for supplying a ramp voltage to said ramp voltage utilization means;
- and
- second resistance means disposed external to said integrated circuit and coupled between said other interface terminal and said juncture for controlling said ramp voltage.
Dependencies are inferred from the claim text.