Function Description
R&S
®
TS-PSU12
20
User Manual 1504.4524.12 ─ 05
5.2.8 Protective mechanisms
A series of protective mechanisms are integrated into the output stage to prevent dam-
age to the R&S TS-PSU12 and externally connected devices. When necessary, these
protective mechanisms turn off the linear regulator of the appropriate channel and
open the relays of the force lines. The LEDs assigned to the channel (CH1 or CH2)
begin to flash. The channel cannot be connected and activated again until the user has
confirmed that the protective mechanism has engaged. Driver function
rspsu_ResetOutputProtection
is used for this purpose. It can also be implicitly
called by resetting the module (
rspsu_reset
). The module software can also be
used to query whether a channel is in voltage or current mode, and whether a protec-
tive mechanism has been triggered.
The module software can also be used to query whether a channel is in voltage or cur-
rent mode, and whether a protective mechanism has been triggered.
1.
Over-voltage protection
If the voltage at the force pins exceeds the programmed threshold value, the pro-
tective mechanism will respond. To ensure effective operation, the value must be
far enough above normal operation so that minor deviations do not cause trigger-
ing.
2.
Current monitoring
High currents may flow if regulation fails or in the event of overload. To prevent
damage, overcurrent protection engages at approximately 120 % of the current
range.
Example:
With a the current range of 500 mA, overcurent protection engages at 650 mA.
3.
Excess temperature protection
Several temperature sensors are built into the R&S TS-PSU12 to protect the linear
regulator. One of these temperature sensors continuously monitors the tempera-
ture on the heat sink of the PSU power module. If the limit value of 70°C is excee-
ded, the protective mechanism for the linear regulator engages. In some applica-
tions, however, (for example PWM mode at high frequency and high current), it is
possible that only the linear controller will heat up very quickly, without the temper-
ature of the heat sink coming close to the limit temperature of 70°C. A temperature
sensor integrated into the linear controller monitors its temperature in addition and
switches off the linear controller when necessary to prevent it from being destroyed
by excess heat. This condition is also detected by the R&S TS-PSU12 and results
in the affected channel being turned off.
4.
Monitoring power supply voltages
If one of the power supply voltages is not correctly applied, this will cause the pro-
tective mechanism to engage and the yellow LED for that channel will begin to
flash.
5.
Current limiting
Power supply/load unit
