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DP8105 5A DC-DC Intelligent dPOL Data Sheet

8V to 14V Input •••• 0.7V to 5.5V Output

BCD.00261 Rev. 1.0, 12 Feb 2013

www.power-one.com

Page 13 of 35

Figure 15 Transient response with non-zero Regulation.

The Load Regulation parameter is an important part

of Current Sharing. It is used to set one dPOL as a

"master", by assigning a lower mV/A load regulation

than all other dPOLs which share the load as

"slaves". The dPOL with the lowest Regulation

parameter sets the effective overall regulation. (See

Current Sharing elsewhere in this document.)

7.2

Sequencing and Tracking

Turn-on delay, turn-off delay, and rising and falling

output voltage slew rates can be programmed in the

dPOL Configure Sequencing window shown in

Figure 16 or directly via the I2C bus by writing into

the DON, DOF, and TC registers, respectively. The

registers are shown in Figure 17, Figure 19, and

Figure 20.

Figure 16. dPOL Configure Sequencing Window

7.2.1

Turn-On Delay

Turn-on delay is defined as an interval from the

application of the Turn-On command until the output

voltage starts ramping up.

DON7

DON6

DON5

DON4

DON2

DON1

DON0

Bit 7

Bit 0

R/W-0

Bit 7:0 DON[7:0]: Turn-on delay time

00h: corresponds to 0ms delay after turn-on command has occurred

…

FFh: corresponds to 255ms delay after turn-on command has occurred

DON3

Figure 17. Turn-On Delay Register DON

7.2.2

Turn-Off Delay

Turn-off delay is defined as an interval from the

application of the Turn-Off command until the output

voltage reaches zero (if the falling slew rate is

programmed) or until both high side and low side

switches are turned off (if the slew rate is not

programmed). Therefore, for the slew rate controlled

turn-off the ramp-down time is included in the turn-off

delay as shown in Figure 18.

Turn-Off

Command

Internal

ramp-down

command

VOUT

User programmed turn-off delay, TDF

Calculated

delay TD

Time

Ramp-down time, TF

Ramp-down time, T

Falling slew

rate dVF/dT

Figure 18. Relationship between Turn-Off Delay and Falling

Slew Rate

As it can be seen from the figure, the internally

calculated delay TD is determined by the equation

below.

OUT

−

For proper operation TD shall be greater than zero.

The appropriate value of the turn-off delay needs to

be programmed to satisfy the condition.

If the falling slew rate control is not utilized, the turn-

off delay only determines an interval from the

application of the Turn-Off command until both high

side and low side switches are turned off. In this

case, the output voltage ramp-down process is

determined by load parameters.

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