L6919E

14/33

Figure 7. Output transient response without (a) and with (b) the droop function

Figure 8. Active Droop Function Circuit

The feedback current is equal to 50

threshold, so the maximum output voltage deviation is equal to:

sunk from the FB pin. The device regulates at the voltage programmed by the VID.

REMOTE VOLTAGE SENSE

A remote sense buffer is integrated into the device to allow output voltage remote sense implementation without

any additional external components. In this way, the output voltage programmed is regulated between the re-

mote buffer inputs compensating motherboard trace losses or connector losses if the device is used for a VRM

module. The very low offset amplifier senses the output voltage remotely through the pins FBR and FBG (FBR

is for the regulated voltage sense while FBG is for the ground sense) and reports this voltage internally at VSEN

pin with unity gain eliminating the errors. Keeping the FBR and FBG traces parallel and guarded by a power

plane results in common mode coupling for any picked-up noise.

If remote sense is not required, it is enough connecting RFB directly to the regulated voltage: VSEN becomes

not connected and still senses the output voltage through the remote buffer. In this case the FBG and FBR pins

must be connected anyway to the regulated voltage (See figure 10).

The remote buffer is included in the trimming chain in order to achieve ±0.5% accuracy on the output voltage

when the RB Is used: eliminating it from the control loop causes the regulation error to be increased by the RB

offset worsening the device performances.

(a)

(b)

ESR DROP

ESR DROP

Ref

COMP

FB

Total Current Info (I

Ref

COMP

FB

Total Current Info (I