AN2829 datasheet(22/32 Pages) STMICROELECTRONICS

Part #	AN2829

Description	Dual step-down controller with auxilary voltages

PDF	32 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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22 / 32 page

Test setup and performance summary

AN2829

22/32

Figure 13.

1.5 V SMPS efficiency

Figure 14.

1.05 V SMPS efficiency

11.5

Power consumption analysis

To measure the consumption of the device in real working conditions, an external power

supply of +5 V is connected to EXT5V.

The two traces on the following figures show the differentiation in the two input currents.

Once the internal linear regulator is turned on, the device consumption increases.

Figure 15 shows the input current consumption measured at VIN+ (including ISHDN) and

the input device current consumption measured by the VCC pin. Both switching sections

work in forced PWM mode. No load is applied on the outputs.

AM01419v1

Efficiency vs load current OUT1=1,5 V

100

0,001

0,010

0,100

1,000

10,000

Load current [A]

SKIP

NASKIP

PWM

AM01420v1

Efficiency vs load curent OUT2=1,05 V

100