IL9961

2013 December, Ver. 00

Figure 6

– LED Driver IL9961 typical output parameters

Driver’s Operation Description

ICs IL9961 make it possible to control all main types of the key volt-boosting converters,

both with the insulated output and the non-insulated one. When the permitting signal arrives at the

gate of the external MOSFET-transistor, the LED-driver starts to build up the internal energy on the

inductance

coil or the transformer’s primary winding, then the given energy, by various ways, de-

pending on the type of the volt-boosting converter, arrives directly to LEDs. The energy, accumu-

lated in the magnetic element, arrives in the output circuit within the time period of switching off the

power MOSFET-transistor, presetting the current in the circuit of LEDs.

old value of the internal supply voltage of the low voltage part of the circuit UVLO, the voltage at

the pin GATE rises, and the external MOSFET-transistor switches over to the open state. The val-

ue of output current is controlled by means of limiting by the external MOSFET-transistor the mean

current of the inductance coil. The voltage, falling at the reading resistor, in a serial connection with

the source of the external MOSFET-transistor, arrives at the input CS IC IL9961. When the given

voltage reaches the threshold value of the comparator actuation, the voltage at the pin GATE re-

mains unchanged during the time, equal to the enable time of GATE prior to actuation of the com-

parator. Thus the trimming is ensured by the current mean value. Then the external MOSFET-

transistor switches over to the closed state. The threshold value of the comparator actuation is

preset inside the circuit and constitutes 272 mV or can alter outside by means of applying voltage

at the input LD.