ISL6334D_09 Datasheet, PDF (14/28 Pages) Intersil Corporation – VR11.1, 4-Phase PWM Controller with Phase Dropping, Droop Disabled and Load Current Monitoring Features

ISL6334D
the error in the reference voltage (output of the DAC) and
offset errors in the OFS current source, remote-sense and
error amplifiers. Intersil specifies the guaranteed tolerance of
the ISL6334D to include the combined tolerances of each of
these elements.
The output of the error amplifier, V_COMP, is compared to
sawtooth waveforms to generate the PWM signals. The
PWM signals control the timing of the Intersil MOSFET
drivers and regulate the converter output to the specified
reference voltage. The internal and external circuitry, which
control voltage regulation, are illustrated in Figure 6.
EXTERNAL CIRCUIT ISL6334D INTERNAL CIRCUIT
R_C C_{C COMP}
R_REF
C_REF
DAC
REF
FB
R_FB
VDIFF
+
-
V_COMP
ERROR AMPLIFIER
V_OUT+
VSEN
+
V_OUT-
RGND
-
DIFFERENTIAL
REMOTE-SENSE
AMPLIFIER
FIGURE 6. OUTPUT VOLTAGE REGULATION LOOP
The ISL6334D incorporates an internal differential remote
sense amplifier in the feedback path. The amplifier removes
the voltage error encountered when measuring the output
voltage relative to the local controller ground reference point,
resulting in a more accurate means of sensing output
voltage. Connect the microprocessor sense pins to the
non-inverting input, VSEN, and inverting input, RGND, of the
remote-sense amplifier. The remote-sense output, V_DIFF, is
connected to the inverting input of the error amplifier through
an external resistor.
A digital-to-analog converter (DAC) generates a reference
voltage based on the state of logic signals at pins VID7
through VID0. The DAC decodes the eight 6-bit logic signal
(VID) into one of the discrete voltages shown in Table 2. All
VID pins have no internal pull-up current sources after t_D3.
After t_D3, each VID input offers a minimum 30µA pull-up to
an internal 2.5V source for use with open-drain outputs. The
pull-up current diminishes to zero above the logic threshold
to protect voltage-sensitive output devices. External pull-up
resistors can augment the pull-up current sources in case
leakage into the driving device is greater than 30µA.
TABLE 2. VR11 VID 8-BIT
VID7 VID6 VID5 VID4 VID3 VID2 VID1 VID0 VOLTAGE
00000000
OFF
00000001
OFF
0 0 0 0 0 0 1 0 1.60000
0 0 0 0 0 0 1 1 1.59375
0 0 0 0 0 1 0 0 1.58750
0 0 0 0 0 1 0 1 1.58125
0 0 0 0 0 1 1 0 1.57500
0 0 0 0 0 1 1 1 1.56875
0 0 0 0 1 0 0 0 1.56250
0 0 0 0 1 0 0 1 1.55625
0 0 0 0 1 0 1 0 1.55000
0 0 0 0 1 0 1 1 1.54375
0 0 0 0 1 1 0 0 1.53750
0 0 0 0 1 1 0 1 1.53125
0 0 0 0 1 1 1 0 1.52500
0 0 0 0 1 1 1 1 1.51875
0 0 0 1 0 0 0 0 1.51250
0 0 0 1 0 0 0 1 1.50625
0 0 0 1 0 0 1 0 1.50000
0 0 0 1 0 0 1 1 1.49375
0 0 0 1 0 1 0 0 1.48750
0 0 0 1 0 1 0 1 1.48125
0 0 0 1 0 1 1 0 1.47500
0 0 0 1 0 1 1 1 1.46875
0 0 0 1 1 0 0 0 1.46250
0 0 0 1 1 0 0 1 1.45625
0 0 0 1 1 0 1 0 1.45000
0 0 0 1 1 0 1 1 1.44375
0 0 0 1 1 1 0 0 1.43750
0 0 0 1 1 1 0 1 1.43125
0 0 0 1 1 1 1 0 1.42500
0 0 0 1 1 1 1 1 1.41875
0 0 1 0 0 0 0 0 1.41250
0 0 1 0 0 0 0 1 1.40625
0 0 1 0 0 0 1 0 1.40000
0 0 1 0 0 0 1 1 1.39375
0 0 1 0 0 1 0 0 1.38750
0 0 1 0 0 1 0 1 1.38125
0 0 1 0 0 1 1 0 1.37500
0 0 1 0 0 1 1 1 1.36875
14
FN6802.1
May 28, 2009