KR960009682A - Horizontal output transistor protection circuit - Google Patents

Abstract

According to the present invention, when the frequency of the horizontal synchronizing signal applied to the horizontal output transistor is disturbed in the horizontal tension circuit unit and the frequency of the horizontal synchronizing signal is increased, the retrace time during the horizontal scanning period becomes shorter and the scanning time becomes longer. This is made in consideration of the fact that the current flowing through the output transistor is increased and the horizontal output transistor is easily destroyed, and thus adversely affects such that the raster does not appear on the screen of the television. When the current flowing above the reference value, the commercial AC power supply is cut off to provide a horizontal output transistor protection circuit to protect the horizontal output transistor from overcurrent.

Accordingly, in accordance with the present invention, the horizontal deflection circuit section 10 for performing the horizontal deflection of the television and the horizontal output transistor 21 for performing the horizontal output by switching by the horizontal synchronous frequency provided from the horizontal deflection circuit section 10 are horizontal. In a television comprising a power circuit section (40) for rectifying an output circuit section (20) and a commercial AC power supply and supplying operating power for a television comprising the horizontal deflection circuit section (10) and the horizontal output circuit section (20), A first level detector 30 connected to an output terminal of the horizontal output transistor 21 and detecting an output level of the output terminal of the horizontal output transistor 21, a frequency generator 31 for generating a reference frequency of a predetermined group; The output level of the reference frequency of the reference frequency and the output level and phase from the horizontal output transistor 21 through the second level detector 31 and the first level detector 30. The comparator 330, which compares the output level according to the reference frequency from the frequency generator 31 through the second level detector 32, receives an output signal of a predetermined level from the comparator 33 and receives an overcurrent state. When the overcurrent state of the horizontal output transistor 21 is detected by the overcurrent detecting unit 34 and the overcurrent detecting unit 34 to detect the microcomputer 46 of the power circuit unit 40 which performs the blocking control of the commercial AC power. And a switching transistor 52 of the power supply circuit 40 which is brought into a conductive state in response to the control control of the commercial AC power supply by means of the commercial AC power supply and controls the relay 53 having a contact formed on the commercial AC power path in an inactive state. Characterized in that configured.

Description

Horizontal output transistor protection circuit

Since this is an open matter, no full text was included.

3 is a diagram showing a circuit configuration of a horizontal output transistor protection circuit according to the present invention.

4 is a diagram illustrating a power supply circuit unit of a melévision to which the horizontal output transistor protection circuit according to the present invention is applied.

Claims (2)

A horizontal output circuit section having a horizontal deflection circuit section 10 for performing horizontal deflection of the television and a horizontal output transistor 21 for switching horizontally by a horizontal synchronizing frequency provided from the horizontal deflection circuit section 10 to perform horizontal output; 20) and a power supply circuit unit 40 for rectifying commercial AC power and supplying operating power of the television, which represents the horizontal deflection circuit unit 10 and the horizontal output circuit unit 20, wherein the horizontal A first level detector 30 connected to the output transistor 21 by an output terminal, the horizontal output transistor 21 detecting the output level of the output terminal, a frequency beacon 31 generating a predetermined reference frequency, and the reference; A second level detector 32 for detecting an output level of frequency, an output level from the horizontal output transistor 21 to which the first level detector 30 is added, and the second level detector 32 through the second level detector 32; A comparator 33 for comparing output levels according to a reference frequency from the frequency generator 31, an overcurrent detector 34 for detecting an overcurrent state by receiving an output signal of a predetermined level from the comparator 33, The high current detection unit 34 detects the overcurrent state of the horizontal output transistor 21 and performs the microcomputer 46 and the microcomputer 46 by the microcomputer 46. And a switching transistor 52 of the power circuit unit 40 which is brought into a conductive state in response to an AC power cutoff control and controls the relay 53 having a contact formed on the commercial AC power path in an inactive state. Horizontal output transistor protection circuit. 2. The comparator (33) according to claim 1, wherein the comparator (33) receives an output signal from the horizontal output transistor (21) at a first input terminal (+) and from the frequency generator (31) at its second input terminal (-). Horizontal output transistor protection circuit characterized in that the horizontal frequency of 15.734KHz is inputted ※ Note: The disclosure is based on the initial application.