AS1310-BTDT-25 查看數據表（PDF） - austriamicrosystems AG

零件编号

产品描述 (功能)

生产厂家

AS1310-BTDT-25

Ultra Low Quiescent Current, Hysteretic DC-DC Step-Up Converter

austriamicrosystems AG 

AS1310

Datasheet - Detailed Description

Figure 13. Simplified Voltage and Current Waveforms

V

0.99VOUT_NOM

VOUT

lid VIND_TOFF

B

a VIN

v VIND_TON

CD

A

ill 0

B

C

D

t TOFF TWAIT

IL

G s IPK

s A nt 0

m te T

TON

SW1_on

SW2_off

TOFF TWAIT

SW2_on

SW1_off

T

VOUT Ripple

T

T

a con Another important relationship is the “volt-seconds” law. Expressed as following:

lVONTON = VOFFTOFF

(EQ 4)

a Voltages are those measured across the inductor during each time segment. Figure 13 shows this graphically with the shaded segments marked

“A & B”. Re-arranging (EQ 4):

ic T--T--O-O---F-N--F- = V----O----U---V-T--I--–N----V----I--N--

(EQ 5)

n The time segment called TWAIT in Figure 13 is a measure of the “hold-up” time of the output capacitor. While the output voltage is above the

threshold (0.99xVOUT), the output is assumed to be in regulation and no further switching occurs.

h 8.1.2 Inductor Choice Example

c For the AS1310 VIN_MIN = 0.9V, VOUT_MAX = 3.3V, (EQ 5) gives Ton=2.66TOFF.

e Let the maximum operating on-time = 1µs.

TNote that this is shorter than the minimum limit on-time of 3.6µs. Therefore from (EQ 5), TOFF = 0.376µs. Using (EQ 3), LMAX is obtained:

LMAX = 1.875µH. The nearest preferred value is 2.2µH.

This value provides the maximum energy storage for the chosen fixed on-time limit at the minimum VIN.

www.austriamicrosystems.com/DC-DC_Step-Up/AS1310

Revision 1.8

9 - 19

Share Link: