Epson LQ 1050 Technical Manual - Page 68

Constant-Voltage Control +24 VDC

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REV.-A The negative terminal of AMP 3 receives VREF (5V) #'. %-. Consequently, the voltage applied to the positive terminal is adjusted to 5V. Therefore, based on Figure 2-23, the output voltage is set to the following value: ~ (R6 + R2) = ~ ohms (9.1 K ohms + 2.4K ohms) = 23.96 V OUTPUT VW Voltage A 3. 3K 9R7K 2R5K $",:. Figure 2-23. Constant-Voltage Control (+24 VDC) AMP 2 operates as follows for over-current control. +24 V is applied to the negative terminal, and the positive terminal will receive an equal voltage when, based on Figure 2-24, a negative current of the following value flows. o"tpu;~o'tage R 9 / R 3 = , , ~~~ms 560 ohms/O.22 ohms = 5.55 [A] If the current exceeds this value, over-current protection is turned on to reduce the output voltage. OUTPUT Voltage + Figure 2-24. Over-Current Protection (OCP) Dead-time control has no bearing in this case, because pin 3 of IC 1 1 is grounded. 2-24

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REV.-A
The negative terminal of AMP 3
receives
V
REF
(5V)
#’.
Consequently, the voltage applied to the positive terminal is adjusted to 5V. Therefore, based on Figure
%-.
2-23, the output voltage is set to the following value:
~
(R6 + R2) =
~
ohms (9.1 K ohms + 2.4K ohms)
= 23.96 V
OUTPUT
VW
Voltage
A
3. 3K
9R7K
2R5K
$“,:.
Figure 2-23. Constant-Voltage Control (+24 VDC)
AMP 2 operates as follows
for over-current control.
+24 V is applied to the negative terminal, and the positive terminal will receive an equal voltage when,
based on Figure 2-24, a negative current of the following value flows.
o“tpu;~o’tage
R9/R3
=
, ,
~~~ms
560
ohms/O.22
ohms
= 5.55 [A]
If the
current exceeds this value, over-current protection is turned on to reduce the output voltage.
OUTPUT
Voltage
+
Figure 2-24. Over-Current Protection
(OCP)
Dead-time control has no bearing in this case, because pin 3 of
IC
1 1 is grounded.
2-24