AN10881
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Application note
Rev. 2 — 26 September 2011
61 of 102
NXP Semiconductors
AN10881
TEA1713 resonant power supply control IC with PFC
The amplitude of the current depends linearly on the boost voltage. At nominal boost
voltage the current is zero and the voltage across the current sense resistor is also
present at the SNSCURHBC pin. At the boost start level SNSBOOST = 1.8 V and the
current is maximum 170
A. The direction of the current, sink or source, depends on the
active gate signal. The voltage drop created across Rcc reduces the voltage amplitude at
the pin, resulting in a higher effective current protection level. The value of Rcc sets the
amount of compensation.
8.7.4 Current measurement circuits
8.7.5 SNSCURHBC layout
Because the SNSCURHBC must be able to accurately sense the measurement signal
cycle-by-cycle at higher frequencies, it is rather susceptible to disturbances. Place the
series resistor Rcc close to the IC to reduce the length of the track that can pick up
disturbing signals. This prevents disturbances on this input. As the impedance of the
measurement resistor is normally low, the signal track between Rcc and the measurement
resistor is not critical regarding disturbance.
Fig 37. SNSCURHBC: resonant current measurement configurations
001aal047
V
BOOST
SNSCURHBC
I
res
17
Rcc
Rm
1 k
Ω
V
BOOST
SNSCURHBC
I
res
0.02 I
res
17
Rcc
C = 1 nF
C = 49 nF
Rm
1 k
Ω
