Application information

L6562AT

16/25

7.5

Comparison between the L6562AT and the L6562

The L6562AT is not a direct drop-in replacement of the L6562, even if both have the same

pin-out. One function (Disable) has been relocated.

Table 2 compares the two devices, i.e. those parameters that may result in different values

of the external components. The parameters that have the most significant impact on the

design, i.e. that definitely require external component changes when converting an L6562-

based design to the L6562AT, are highlighted in bold.

The lower value (-36%) for the clamp level of the current sense reference voltage allows the

use of a lower sense resistor for the same peak current, with a proportional reduction of the

associated power dissipation. Essentially, the advantage is the reduction of the power

dissipated in a single point (hotspot), which is a considerable benefit in applications where

heat removal is critical, e.g. in adapters enclosed in a sealed plastic case. The lower value

for the dynamic OVP triggering current allows the use of a higher resistance value (+48%)

for the upper resistor of the divider sensing the output voltage of the PFC stage (keeping the

same overvoltage level) with no significant increase of noise sensitivity. This reduction goes

in favor of standby consumption in applications required to comply with energy saving

regulations.

Table 6.

L6562AT vs L6562

Parameter

L6562

L6562AT

IC turn-on and turn-off thresholds (typ.)

12/9.5 V

12.5/10 V

Turn-off threshold spread (max.)

±0.8 V

±0.5 V

IC consumption before start-up (max.)

70 uA

60 uA

Multiplier gain (typ.)

0.6

0.38

Current sense reference clamp (typ.)

1.7 V

1.08 V

Current sense propagation delay (delay-to-output) (typ.)

200 ns

175 ns

Dynamic OVP triggering current (typ.)

40 µA

27 µA

ZCD arm/trigger/clamp thresholds (typ.)

2.1/1.4/0.7 V

1.4/0.7/0 V

Enable threshold (typ.)

1.

Function located on pin 5 (ZCD)

2.

Function located on pin 1 (INV)

Gate-driver internal drop (max.)

2.6 V

2.2 V

Leading-edge blanking on current sense

No

Yes

Reference voltage accuracy (overall)

2.4%

1.8%