AN10881
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© NXP B.V. 2011. All rights reserved.
Application note
Rev. 2 — 26 September 2011
76 of 102
NXP Semiconductors
AN10881
TEA1713 resonant power supply control IC with PFC
10.3.3.3
UVP functional and OVP disabled
In some applications preventing the activation of the overvoltage protection on SNSOUT
by disabling OVP can be required. This can be realized by adding a circuit that prevents
the voltage on SNSOUT from exceeding 3.5 V.
As a practical example, the voltage on SNSOUT can be prevented from exceeding the
preset voltage by externally adding a low impedance resistive divider, with a fixed voltage,
and connecting it to SNSOUT via a diode. This simple circuit is not accurate but it does
provide the basic capability to disable the OVP function of SNSOUT.
Remark:
The diode is blocking for lower voltage values on SNSOUT so that the
undervoltage protection is still functional.
Another possibility is to add a Zener diode function on SNSOUT to limit the voltage on this
pin.
Fig 50. Example of disabling the UVP function of SNSOUT
001aal059
100
μ
A
1.5 V
SNSOUT
SUPREG = 10.9 V
1N4148
8.2 k
Ω
3.3 k
Ω
V
AUXILIARY
5
TEA1713
OVP
latched shutdown
3.5 V
COMP
UVP
protection timer
2.35 V
COMP
HOLD HBC
1.1 V
COMP
HOLD PFC
0.4 V
COMP
