at83c26 ATMEL Corporation, at83c26 Datasheet - Page 21

• Manufacturer Part Number: at83c26
• Description: Multiple Smart Card Reader Interface With Power Management
• Manufacturer: ATMEL Corporation

DC/DC B converter
7511D–SCR–02/07
Figure 9. DC/DC A Converter Initialization Procedure
The DC/DC B converter is controlled by DCDCB register.
The DC/DC B converter can be switched on even if CPRES2 pin remains inactive.
A write operation in VDCB[1:0] (0x01, 0x02, 0x03) starts the DC/DC. When the output voltage
remains within the voltage range specified by VDCB_OK[1:0], the VDCB_OK bit is set.
The DC/DC B Converter can work in two different modes which are selected by STEPREGB:
•
•
The current drawn from power supply by the DC/DC B converter is controlled during the startup
phase in order to avoid high transient current mainly in Pump Mode which could cause the
power supply voltage to drop dramatically. This control is done by means of bits DEM-
BOOSTB[1:0], which increases progressively the startup current level.
Pump Mode (STEPREGB = 0): an external inductance of 10 µH must be connected
between pins LIB and VCC. VCC can be higher or lower than selected voltage.
Regulator mode (STEPREGB = 1): no external inductance is required but VCC must be
always higher than selected voltage+0.3V.
DEMBOOSTA[1:0]
Increment
DEMBOOSTA[1:0]=[0:0]
Set Time-out to 3 ms
DC/DC A Converter
Initialization Failure
DEMBOOSTA[1:0]
is at Maximum?
VCARD_OK1=1
Time-out
Expired
END
DEMBOOSTA[1:0]
current overflow
to adjust the
Decrement
END
AT83C26
21