Called ICL88xx, up to 125W can be delivered in primary-side-regulated (right) and opto-coupler secondary-side-regulated configurations. They are optimised as secondary-side regulated constant-voltage output controllers.
- ICL8800 is the basic variant
- ICL8810 has added burst-mode operation for <100mW stand-by consumption “and flicker-free deep dimming down to 0.1%” according to the company. It is intended for use with a host microcontroller in smart applications
- ICL8820 is the fully-featured variant, additionally equipped with input jittering to modify EMI performance for meeting specifications, particularly in emergency lighting, and power limitation.
Operation is across 90 to 300Vac and 45 to 66Hz using a quasi-resonant topology, controlling the on-time and switching on at the first valley through zero-crossing detection to maximises efficiency. Maximum on-time can be set using the zero-crossing series resistance.
Switching frequency depends on the resonant frequency of the transformer and the mosfet. To reduce relative power, the controller reduces the on-time. At certain relative power levels, the controller also starts increasing the valley to avoid high frequencies. The on-time is compensated to ensure constant relative power for the change of the valley. Off-time is limited to 47µs to keep switching outside the audible range – switching typically remains between 20kHz and 150kHz, depending on component selection.
Overall, conduction mode is discontinuous at mid to light load and critical at high load. When ICL8810 and ICL8820 enter burst mode, repetition frequency is approximately four times the AC input frequency.
Protections include: internal over-temperature , output over-voltage, over-current brown-in, brown-out, open-loop and input over-voltage.
The 125W limitation comes from the gate drive capability for the external switching mosfet – the company suggests its own CoolMOS P7 devices.
Packaging is 5 x 6mm 8pin SMD PG-DSO-8.
As well as lighting, use is foreseen in adapters, flat TVs, all-in-one PCs and monitors.
Outside this market segment, up to 125 W profit from the ICL88xx family
The ICL88xx product page can be found here