tea1781 NXP Semiconductors, tea1781 Datasheet - Page 20

• Manufacturer Part Number: tea1781
• Description: Greenchip Pc Secondary Control Ics
• Manufacturer: NXP Semiconductors

NXP Semiconductors
8. Limiting values
TEA1781_82_1
Preliminary data sheet
7.12.6 System restart
If an OTP is detected all main outputs will be switched off, but the 5 V standby output
remains on.
If an OCP, OVP, or OTP is detected on one of the main outputs, all these outputs are
switched off and latched. A OCP or OVP detection on the 5 V standby will switch off its
output but it will be resumed again at the next cycle.
All outputs can be disabled individually by disabling the bidirectional switch (SR / SB).
Disabling an output will resolve the reason why Protection mode was entered, which can
be an OVP, OCP or OTP.
If a certain time after entering Protection mode (t
detects an OCP or OVP, the secondary side enters the system restart mode. In this mode
the primary side is switched off via the opto coupler, followed by a safe restart. A
continuous error could be caused by a shorted SB switch, for example.
If a small increase of temperature is detected because of an OTP after entering Protection
mode, the system will also turn off the primary side.
So normally, an OCP, OVP or OTP will switch off the secondary outputs. Only when an
OCP, OVP or OTP remains after the outputs are switched off, will the primary side be
switched off. In that case the 5 V standby output will also drop.
Table 5.
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
TEA1781T
V
V
I
V
V
V
V
V
V
V
V
V
ocp
DF_5V
VSTARTUP
CS_5V
VOUT_5V
VSENSE_5V
VNTC
ENABLE
PGND_5V
DD
PGND_3V3
PWROK
Limiting values
Parameter
voltage on pin DF_5V
voltage on pin
VSTARTUP
overcurrent protection
current
voltage on pin CS_5V
voltage on pin
VOUT_5V
voltage on pin
VSENSE_5V
voltage on pin VNTC
voltage on pin
ENABLE
voltage on pin
PGND_5V
supply voltage
voltage on pin
PGND_3V3
voltage on pin PWROK
Rev. 01 — 13 February 2009
Conditions
TEA1781T; TEA1782T
d(restart)
GreenChip PC secondary control ICs
( 500 s)) the system still
Min
-0.8
7
0.4
250
0.4
0.4
0.4
0.4
0.4
0.4
0.8
0.4
© NXP B.V. 2009. All rights reserved.
Max
+40
+75
+80
+7
+7
+7
+7
+13
+0.8
+13
+0.8
+13
Unit
V
V
V
V
V
V
V
V
V
V
V
20 of 32
A