4 Function
4.1 Overcurrent protection
¡
Over Current Protection (OCP) is built-in and works at 105% of
the rated current or higher. However, use in an overcurrent situa-
tion must be avoided whenever possible.
The output voltage of the power module will recover automatically
when the fault causing overcurrent is corrected.
When the output voltage drops after OCP works, the power mod-
ule enters a ”hiccup mode” where it repeatedly turns on and off at
a certain frequency.
4.2 Overvoltage protection
¡
The overvoltage protection circuit is built-in. The DC input will be
shut down if overvoltage protection is in operation.
The output voltage of the power module will recover automatically
when the fault causing over voltage is corrected.
Remarks :
Please note that devices inside the power supply might fail when
voltage more than rated output voltage is applied to output pin of
the power supply. This could happen when the customer tests the
overvoltage performance of the unit.
4.3 Thermal protection
¡
When the power supply temperature is kept above 120
C
, the
thermal protection will be activated and simultaneously shut down
the output.
The output voltage of the power supply will recover automatically
when the unit is cool down.
¿
-U
¡
Option ”-U” means output is shut down when the abovementioned
protection circuit is activated.
If this happens, protection circuit can be inactivated by cycling
the DC input power off for at least 1 second or toggling Remote
ON/OFF signal.
4.4 Remote ON/OFF
¡
Remote ON/OFF circuit is built-in on the input side (RC).
The ground pin of input side remote ON/OFF circuit is ”-VIN” pin.
Table 4.1.1 Specification of Remote ON/OFF(CHS80,CHS200)
ON/OFF
logic
Between RC and -VIN
Output
voltage
Standard Negative
L level(0 - 0.8V) or short
ON
H level(2.0 - 7.0V) or open
OFF
Optional -R
Positive
L level(0 - 0.8V) or short
OFF
H level(2.0 - 7.0V) or open
ON
When RC is ”Low” level, fan out current is 0.1mA typ. When Vcc is applied,
use 2.0
[
Vcc
[
7.0V.
3.2 Wiring output pin
¡
When the CHS series supplies the pulse current for the pulse
load, please install a capacitor Co bVOUT and -VOUT
pins.
Recommended capacitance of Co is shown in Table 3.2, 3.3.
¡
If output current decreases rapidly, output voltage rises transiently
and the overvoltage protection circuit may operate.
In this case, please install a capacitor Co.
¡
Select a high frequency type capacitor. Output ripple and startup
waveform may be influenced by ESR-ESL of the capacitor and the
wiring impedance.
¡
Make sure that ripple current of Co is than its rating.
Table 3.2 Recommended capacitance Co (CHS60, CHS80, CHS120)
No. Output voltage
CHS60
CHS80
CHS120
1
3.3V
0 - 20,000 F
0 - 20,000 F
0 - 20,000 F
2
5V
0 - 10,000 F
0 - 10,000 F
0 - 10,000 F
3
12V
0 - 2,200 F
0 - 1,000 F
0 - 2,200 F
4
15V
-
-
0 - 2,200 F
Table 3.3 Recommended capacitance Co
(CHS200/CHS300/CHS380/CHS400/CHS500/CHS700)
No. Output voltage CHS200/CHS300/
CHS380
CHS400/CHS500
CHS700
1
3.3V
0 - 40,000 F
-
-
2
5V
0 - 20,000 F
-
-
3
10V
0 - 2,200 F
0 - 4,000 F
-
4
12V
0 - 2,200 F
0 - 4,000 F
0 - 10,000 F
5
15V
0 - 2,200 F
-
-
6
24V
-
0 - 3,300 F
-
¡
Ripple and Ripple Noise are measured, as shown in the Fig.3.3.
Cin is shown in Table 2.1.
Oscilloscope
BW:100MHz
1.5m 50
W
Coaxial cable
R
C
R=50
W
F
Load
50mm
+VIN
-VIN
DC
Input
+
Measuring
board
RC
+VOUT
-VOUT
-S
+S
C=0.01
Cin
Co
Output voltage
Co
10 - 15V
22 F
24V
0.1 F
Fig.3.3 Measuring method of Ripple and Ripple Noise
CHS-32
DC-DC Converters Bus Converter.Power Module Type
Instruction Manual