TEA1733MT

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© NXP B.V. 2011. All rights reserved.

Preliminary data sheet

Rev. 1 — 4 February 2011

8 of 20

NXP Semiconductors

TEA1733MT

GreenChip SMPS control IC

7.9 Current mode control (ISENSE pin)

Current mode control is used for its good line regulation.

The primary current is sensed by the ISENSE pin across an external resistor R9 (see

Figure 3) and compared with an internal control voltage. The internal control voltage is

proportional to the CTRL pin voltage (see Figure 6).

Leading edge blanking prevents false triggering due to capacitive discharge when

switching on the external power switch (see Figure 7).

7.10 Overpower or high/low line compensation (VINSENSE and

ISENSE pins)

The overpower compensation function can be used to realize a maximum output power

which is nearly constant over the full input mains.

The overpower compensation circuit measures the input voltage on the VINSENSE pin

and outputs a proportionally dependent current on the ISENSE pin. The DC voltage

across the soft start resistor limits the maximum peak current on the current sense resistor

(see Figure 8).

Fig 6.

Peak current control

Fig 7.

Leading edge blanking

frequency

reduction

0.2

0.4

0.6

0

04

3

12

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(V)

t

014aaa932