AS1326(2007) 查看數據表（PDF） - austriamicrosystems AG

零件编号

产品描述 (功能)

生产厂家

AS1326
(Rev.:2007)

High Current, 0.8A DC-DC Step-Up Converters

austriamicrosystems AG 

AS1326

Data Sheet - Application Information

Setting the Switch Current Limit

The ISET pin is used to adjust the inductor current limit and to implement the soft-start feature.

With pin ISET connected to pin REF, the inductor current limit is set to 1.6A. With ISET connected to a resistor-divider

network from pin REF to GND, the current limit is calculated as:

ILIMIT

=

1.6A

⋅

⎛

⎝

1-V---.-I2--S--5-E---V-T-⎠⎞

(EQ 2)

Soft Start

The soft-start feature can be implemented by placing a resistor between pin ISET and pin REF (see Figure 21) and a

capacitor between pin ISET and GND.

Figure 21. Circuit for Soft-Start with Maximum Switch Current Limit

10nF

RSS

≥220kΩ

ILIMIT = 1.6A

CSS

tSS = Rss x CSS

2

REF

1

ISET

AS1326A/

AS1326B

At power-up, ISET is 0V and the LX current is zero. As the capacitor voltage rises, the current increases and the output

voltage rises. The soft-start time constant is:

tSS = RSS x CSS

(EQ 3)

Where:

RSS ≥ 220kΩ.

Note: Placing a capacitor across the lower resistor of the current-limiting resistor-divider network enables both the

current-limit and soft-start (see Figure 22).

Figure 22. Application Circuit for Soft-Start with Reduced Switch Current Limit

10nF

RSS

≥220kΩ

RSS2

CSS

2

REF

1

ISET

AS1326A/

AS1326B

( ) ILIMIT = 1.6A

Rss2

Rss1 + Rss2

tSS = (Rss1 || Rss2) CSS

www.austriamicrosystems.com

Revision 1.02

12 - 18

Share Link: