NXP Semiconductors AN10907, Примечание к применению

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Application note Rev. 1 — 28 December 2010 64 of 82
NXP Semiconductors
AN10907
TEA1613T resonant power supply control IC
10.4 Protection timer
The TEA1613T has a programmable timer that is used for the timing of several forms of
protection. The timer is basically used in two ways:
•
As a protection timer - the time that an error exists before the system stops operation
•
As a restart timer - the time between stopping and restarting operation
The values for both types of timer can be independently preset by an external resistor and
capacitor connected to RCPROT.
10.4.1 Block diagram of the RCPROT function
10.4.1.1 RCPROT working as protection timer
Figure 50 demonstrates the operation of the protection timer. When an error condition
occurs, a fixed current of 100

A flows from the RCPROT pin and charges the external
capacitor. Due to the external resistor, the voltage rises exponentially. The protection time
Fig 49. Block diagram of the RCPROT function
001aal472
RCPROT
C R
2 mA 100
μ
A
CONTROL
COMP
4 V
0.5 V
TEA1613
COMP
Fig 50. RCPROT protection timer operation
passed
0
0
none
present
short
error
long
error
repetitive
error
4 V
100
μ
A
I
RCPROT
Error
V
RCPROT
t
Protection time
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