CS5332GDWR28 datasheet(15/20 Pages) ONSEMI

15 / 20 page

CS5332

http://onsemi.com

module. If the module is powered apart from the intended

application, the feedback will be left open. On a

motherboard, the feedback path might be broken when the

processor socket is left open. Without the feedback

connection the output voltage is likely to exceed the

intended voltage. To protect the circuit from overvoltage

conditions, a resistor can be connected between the local

output voltage and the remote sense line as shown in Figure 16.

Figure 16. Remote Sense Connection

Remote

Sense

Line

100 Ω

CSREF Network

VFB Network

Local VOUT

Remote VOUT

Soft Start Enable, and Hiccup Mode

A capacitor between the Soft Start pin and GND controls

Soft Start and hiccup mode slopes. A 0.1 μF capacitor with

30 μA charge current will allow the output to ramp up at 0.3

V/ms or 1.5 V in 5.0 ms at start−up.

When a fault is detected due to overcurrent or UVLO the

converter will enter a low duty cycle hiccup mode. During

hiccup mode the converter will not switch from the time a

fault is detected until the Soft Start capacitor has discharged

below the Soft Start Discharge Threshold and then charged

back up above the Channel Start Up Offset.

The Soft Start pin will disable the converter when pulled

below 0.3 V.

Layout Guidelines

With the fast rise, high output currents of microprocessor

applications, parasitic inductance and resistance should be

considered when laying out the power, filter and feedback

signal sections of the board. Typically, a multi−layer board

with at least one ground plane is recommended. If the layout

is such that high currents can exist in the ground plane

underneath the controller or control circuitry, the ground

plane can be slotted to reroute the currents away from the

controller. The slots should typically not be placed between

the controller and the output voltage or in the return path of

the gate drive. Additional power and ground planes or

islands can be added as required for a particular layout.

Gate drives experience high di/dt during switching and the

inductance of gate drive traces should be minimized. Gate

drive traces should be kept as short and wide as practical and

should have a return path directly below the gate trace.

Output filter components should be placed on wide planes

connected directly to the load to minimize resistive drops

during heavy loads and inductive drops and ringing during

transients. If required, the planes for the output voltage and

return can be interleaved to minimize inductance between

the filter and load.

Voltage feedback should be taken from a point of the

output or the output filter that doesn’t favor any one phase.

If the feedback connection is closer to one inductor than the

others the ripple associated with that phase may appear

larger than the ripple associated with the other phases and

poor current sharing can result.

The current sense signal is typically tens of milli−volts.

Noise pick−up should be avoided wherever possible.

Current feedback traces should be routed away from noisy

areas such as switch nodes and gate drive signals. The paths

should be matched as well as possible. It is especially

important that all current sense signals be picked off at

similar points for accurate current sharing. If the current

signal is taken from a place other than directly at the inductor

any additional resistance between the pick−off point and the

inductor appears as part of the inherent inductor resistance

and should be considered in design calculations. Capacitors

for the current feedback networks should be placed as close

to the current sense pins as practical.

CS5332GDWR28 датащи(PDF) 15 Page - ON Semiconductor

CS5332GDWR28 датащи(HTML) 15 Page - ON Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

датащи скачать

ссылки URL