ST1CC40 datasheet(25/37 Pages) STMICROELECTRONICS

Part #	ST1CC40

Description	3 A monolithic step-down current source with synchronous rectification

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

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DocID18279 Rev 5

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ST1CC40

Application information



Switching losses due to turning ON and OFF. These are derived using Equation 29:

Equation 29

where TRISE and TFALL represent the switching times of the power element that causes the

switching losses when driving an inductive load (see Figure 14). TSW is the equivalent

switching time.

Figure 14. Switching losses

Quiescent current losses.

Equation 30

Example (see Section : Example):

VIN = 12 V, VFW_LED = 3.5 V, nLED = 2, ILED = 700 mA

The typical output voltage is:

Equation 31

RDSON_HS has a typical value of 95 m and RDS(on)_LS is 69 m at 25 °C.

For the calculation we can estimate RDS(on)_HS = 140 m and RDS(on)_LS = 100 mas

a consequence of TJ increase during the operation.

TSW_EQ is approximately 12 ns.

IQ has a typical value of 1.5 mA at VIN = 12 V.

PSW

VIN IOUT

TRISE TFALL



----------------------------------------- FSW VIN

IOUT TSW_EQ FSW





AM14826v1

VIN IQ



VOUT

nLED VFW_LED VFB



7,1V

ST1CC40 Datasheet(PDF) 25 Page - STMicroelectronics