US 4,789,896 AGranted

Vertical synchronizing pulse generating circuit

AssigneeSanyo Electric Co., Ltd.

InventorsHiroyasu Kishi, Hiromi Arai

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Abstract

The present invention relates to a vertical synchronizing pulse generating circuit in a television receiver, wherein a vertical synchronizing separation circuit (VS) is so composed not as to directly integrate pulses sequentially outputted from a composite synchronizing separation circuit, but as to integrate a small amount of electric current outputted according to the sequentially outputted pulses. Accordingly, it is possible to reduce the capacity of a capacitor (22) used for the integration and at the same time, it is possible to incorporate the capacitor in an integrated circuit, Thus, it is possible to decrease the number of pins provided to the integrated circuit. Furthermore, the small amount of electric current can be regulated according to the electric current flowing through an externally connected load (28).

Claims5

Dependent claims

A vertical synchronizing pulse generator comprising:

a first vertical synchronizing signal separation means (VS) for separating a vertical synchronizing signal included in a composite video signal;
a signal generating means (9) for generating a signal having a frequency which is a predetermined number times as many as the frequency of a horizontal synchronizing signal included in the composite video signal;
a freguency dividing means (8), which receives an output signal from said first vertical synchronizing signal separation means as a reset signal and also receives said signal from said signal generating means as a clock signal, for dividing said clock signal;
an output means (25, 24, and 29) for supplying an output signal to a load according to an output from said frequency dividing means;
and
a sensitivity controlling means (26, 27, and 14 to 19) for controlling a separation sensitivity of said first vertical synchronizing signal separation means according to the electric current flowing through the load.

3 more elements

Dependencies are inferred from the claim text.