9
- When the MOSFET is ON, the STR-F6653 internal capacitor C1 is charged at the constant voltage 6.5V.
At the same time, the voltage at pin 1 (OCP / FB) increases with the same waveform as the MOSFET drain current.
- When the pin 1 voltage reaches the threshold voltage V
TH1
= 0.73V, the STR-F6653 internal comparator 1 starts operating.
The STR-F6653 internal oscillator is inverted and the MOSFET turns OFF.
- When the MOSFET turns OFF, charging of STR-F6653 internal capacitor C1 is released and C1 starts discharging by the
STR-F6653 internal resistance R1. So, C1 voltage starts falling in accordance to the gradient regulated by the constant dis-
charging time of C1 and R1. So, this means that the fixed time determined by C1 and R1 is the OFF-time of the MOSFET.
- When C1 voltage falls to around 3.7V, the STR-F6653 internal oscillator is reversed again and the MOSFET turns ON. C1 is
quickly charged to around 6.5V
The MOSFET continues to oscillate by repeating the above procedure.
ON ON ON OFF
OFF
OFF
M O S F E T
switching ON / OFF
V
D S
(M OSFET drain - source voltage)
I
D
(M OSFET drain current)
Pin 1
(OCP / FB)
0V
0.73 V
(STR -F6653
internal capacitor)
C1
3.7 V
6.5 V
1
3
2
4
Waveforms during oscillating operation
APPENDIX
FUNCTIONAL DESCRIPTION
Summary of Contents for DTA-14V1
Page 26: ...6 CIRCUIT BLOCK DIAGRAM...
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Page 30: ...10 EXPLODED VIEW 1 14V3...
Page 31: ...11 EXPLODED VIEW 2 20V3...
Page 32: ...12 EXPLODED VIEW 3 21V3...
Page 33: ...13 PRINTED CIRCUIT BOARD CIRCUIT DIAGRAM 6 SERVO SYSCON CEC CIRCUIT DIAGRAM T DECK...
Page 59: ...19 IC DESCRIPTION APPENDIX...
Page 62: ...22 APPENDIX IC DESCRIPTION...
