ST1CC40 datasheet(9/37 Pages) STMICROELECTRONICS

No de pièce	ST1CC40

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

PDF	37 Pages

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Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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DocID18279 Rev 5

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ST1CC40

Functional description

The ST1CC40 device is based on a “peak current mode” architecture with fixed frequency

control. As a consequence, the intersection between the error amplifier output and the

sensed inductor current generates the control signal to drive the power switch.

The main internal blocks shown in the block diagram in Figure 3 are:



High-side and low-side embedded power element for synchronous rectification



A fully integrated sawtooth oscillator with a typical frequency of 850 kHz



A transconductance error amplifier



A high-side current sense amplifier to track the inductor current



A pulse width modulator (PWM) comparator and the circuitry necessary to drive the

internal power element



The soft-start circuitry to decrease the inrush current at power-up



The current limitation circuit based on the pulse-by-pulse current protection with

frequency divider



The inhibit circuitry



The thermal protection function circuitry

Figure 3. ST1CC40 block diagram

ST1CC40 Fiches technique(PDF) 9 Page - STMicroelectronics