Ver1.1

9

LD1611

High Power LED Driver

11.4 Layout Considerations

For high frequency and high current switching power supplies, layout is an important design step.

To reduce switching losses, the switch rise and fall times are made as short as possible.

Minimize the length and area of all traces connected to the switch and always use a ground plane under

the switching regulator to inter-plane coupling.

The loop including LEDs, the PFM switch and schottky diode contains high current rising and falling and

should be kept as short as possible.

The input capacitor needs not only to be close to the VIN pin, but also to the GND pin in order to reduce

the supply ripple.

11.5 Thermal Considerations

The maximum IC junction temperature should be restricted to 125℃ under normal operating conditions.

Calculate the maximum allowable dissipation, P

to P

P

JA

where, T