Because of its VF value LED characteristic reason can’t do the same, as the temperature and the current size also some VF value will also be changing, generally not suitable for parallel design. But in some cases had to solve a driver in fluorescent led lights. The design can do some reference for everybody.
Attention to VF value FenDang, grade VF value in the same products LED to use it, the product can ensure that error in current 1 mA, LED the work within the relatively constant current state.
The integrated transistor can keep every road fluorescent led replacement that the transistor in the same temperature environment, the same process conditions produced the beta value, can be a guarantee that every road current basis. Constant current part in the demand is not very high conditions can be designed, stable voltage or stable PWM V voltage value of the transistor bias after driving, and does basic constant flow.
Precision of IC does constant current source of reference. R can set IC output current, once determined R resistance can use fixed resistance instead. Many of the device transistor integrated user can reduce the number of IC use, so as to reduce the cost of product design.
Linear high power LED constant current output can be used in parallel. In product design we tend to find bigger current driver IC, General 2 an above is very rare, nominal 2 A IC also will not always be able to limit use. More than 1 A IC technology cost reasons are the outer tube MOS, external MOS GuanXianLu complex, reduced reliability. Parallel is the effective way to use the design.
The DD312 parallel reference design direct drive 3 star is WLED 6. Can Make PWM control signal need proper isolation, avoid mutual interference and drive capacity problems. EN can make voltage must comply with the specification requirements, don’t too high voltage damage EN feet. General IC compression is refers to the load and power. There is no indication of the incentive voltage please don’t more than 5 V design.
Like the best in one end of the fluorescent led retrofit can also parallel design drive, in fact IC is working alone, and the last in the flow together. DC-DC way is to work at higher frequencies, note that the PCB cloth avoids across the board design, each filter, bypass capacitors you stay with IC near, load current will be at last and can.