tea1781 NXP Semiconductors, tea1781 Datasheet - Page 17

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

NXP Semiconductors
TEA1781_82_1
Preliminary data sheet
7.12.2 Undervoltage protection
7.12.3 Overvoltage protection
7.12.4 Overcurrent protection
When the 5 V standby voltage / current exceeds its upper limit the output will be switched
off. It will be turned on again at the next cycle as soon as the output voltage/current level
drops below the upper limit.
When undervoltage is detected on one of the main outputs (3.3 V, 5 V, 12 V) the pin
PGOOD is pulled low which again pulls the PWROK signal low.
When undervoltage on the 5 V standby output is detected, the system switches to
Standby mode and returns back to Normal mode once the 5 V standby is above its
minimum level.
As stated previously, all outputs have an OVP function. However, the 12 V1 and 12 V2
have one OVP function. It is assumed that the 12 V2 is directly coupled to the 12 V1
voltage and therefore these voltages are about equal.
All OVP levels are integrated and cannot be set externally.
The OCP levels can be set externally. The maximum output current of the 12 V1 and 12
V2 are supposed to be about equal, therefore have the same OCP setting.
gives the 12 V OCP block diagram.
Rev. 01 — 13 February 2009
TEA1781T; TEA1782T
GreenChip PC secondary control ICs
© NXP B.V. 2009. All rights reserved.
Figure 15
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