SC493

21

Register Map

Address

D7

D6

D5

D4

D3

D2

D1

D0

Access Reset

Description

00h

PGD

DCM

DNS

BO

ILIM

OT

OVO

UVO

RO

40h

Status Register

01h

EnIntLd

CLF

ENSW

R/W

01h

Control Register 1

02h

UPSV0

POD2

POD1

POD0

Freq1

Freq0

R/W

20h

Control Register 2

03h

UPSV1

SST2

SST1

SST0

PSV1

PSV0

R/W

2Eh

Control Register 3

04h

VFBadj4

VFBadj3

VFBadj2

VFBadj1

VFBadj0

R/W

0Fh

Control Register 4

06h

Margin2

Margin1

Margin0

R/W

3Bh

Control Register 6

Definition of Registers and Bits

Status and Flag Bits Description — Register 0

A status bit reflects the current state of the converter. It becomes high when the specified condition has occurred and

turns low when the specified condition has disappeared. A flag bit becomes high when the specified condition has

occurred and will not turn low when the specified condition has disappeared.

Name

Bit

Definition

Description

UVO

00h[0]

Under Voltage Output Flag

Flag bit when high indicates that the output voltage fell below 70% of the regulation level

while being current limited.

OVO

00h[1]

Over Voltage Output Flag

Flag bit when high indicates output voltage has been above the regulation level by 20%.

OT

00h[2]

Over Temperature Flag

Flag bit when high indicates that the over temperature circuit has tripped.

ILIM

00h[3]

Output Current Limit Flag

Flag bit when high indicates that the inductor current threshold has been reached.

BO

00h[4]

Brown Out Flag

Flag bit when high indicates that the FB voltage has fallen below PGD falling threshold (80%)

with the device not in current limit. This normally means the output under voltage has been

caused by low input voltage.

DNS

00h[5]

Did Not Start Flag

Flag bit when high indicates that the FB voltage did not reach the power good rising thresh-

old (90%) within the predetermined time. This time interval is the programmed soft start time.

The power good delay is 10% of the programmed soft start time.

DCM

00h[6]

Discontinuous Mode

Status

Status bit when high indicates that the part is operating in discontinuous mode. The part is

only permitted to operate in DCM if PSAVE or UPSAVE is enabled. The part also enters into

DCM mode before the soft start process is complete. Therefore, in the shut down state and

during the soft start process, this bit is also set.

PGD

00h[7]

Power Good Status

Status bit when high indicates that the PGD pin is not being pulled low and therefore the

output is within regulation by +20%.

Notes:

(1) Always write 0

(2) Always write 1