ISL68200 Datasheet, PDF (26/32 Pages) Intersil Corporation – Single-Phase R4 Digital Hybrid PWM Controller with Integrated Driver

ISL68200
TABLE 11. SMBus, PMBus, AND I²C SUPPORTED COMMANDS (Continued)
COMMAND
CODE
ACCESS
WORD
LENGTH
(BYTE)
DEFAULT
VALUE
COMMAND NAME
DESCRIPTION
8Dh[15:0]
R
TWO
READ_TEMP
VR Temperature
TEMP (°C) = 1/{ln[Rup*HEX2DEC(8D hex
data)/(511 - HEX2DEC(8D hex data)/RNTC(at +25°C)]/Beta +
1/298.15} -273.15
98h[7:0]
R
ONE
02h
PMBUS_REVISION Indicates PMBus Revision 1.2
AD[15:0] BLOCK R
TWO
8200h
IC_DEVICE_ID ISL68200 Device ID
AE[15:0] BLOCK R
TWO
0003h
IC_DEVICE_REVISION ISL68200 Device Revision
D0[0:0]
R/W
ONE
PROG2[7:7]
ENABLE_PFM PFM OPERATION
0h = PFM Enabled (DCM at light load)
1h = PFM Disabled (always CCM mode)
D1[1:0]
R/W
ONE
PROG2[6:5]
TEMP_COMP
Thermal Compensation:
0h = 30°C; 01h = 15°C; 02h = 5°C; 03h = OFF
D2[0:0]
R/W
ONE
PROG3[7:7] ENABLE_ULTRASONIC Ultrasonic PFM Enable
0h = 25kHz Clamp Disabled
1h = 25kHz Clamp Enabled
D3[0:0]
R/W
ONE
PROG3[6:6]
OCP_BEHAVIOR Set latch or infinite retry for OCP fault:
0h = Retry every 9ms; 01 = Latch-OFF
D4[2:0]
R/W
ONE
PROG3[2:0]
AV_GAIN
R4 AV GAIN (PROG4, AV Gain Multiplier = 2x)
0h = 84; 1h = 73; 2h = 61; 3h = 49
4h = 38; 5h = 26; 6h = 14; 7h = 2
R4 AV GAIN (PROG4, AV Gain Multiplier = 1x)
0h = 42; 1h = 36.5; 2h = 30.5; 3h = 29.5
4h = 19; 5h = 13; 6h = 7; 7h = 1
D5{2:0]
R/W
ONE
PROG4[7:5]
RAMP_RATE
Soft-Start and Margining DVID Rate (mV/µs)
0h = 1.25; 1h = 2.5; 2h = 5; 3h = 10; 4h = 0.078; 5h = 0.157
6h = 0.315; 7h = 0.625;
D6[1:0]
R/W
ONE
PROG4[4:3]
SET_RR
Set RR
0h = 200k; 01h = 400k; 02h = 600k; 03h = 800k
DC[7:0]
R
ONE
READ_PROG1 Read PROG1
DD{7:0]
R
ONE
READ_PROG2 Read PROG2
DE[7:0]
R
ONE
READ_PROG3 Read PROG3
DF[7:0]
R
ONE
READ_PROG4 Read PROG4
NOTE: Series bus communication is valid 5.5m (typically, worst 6.5ms) after VCC, VIN, 7VLDO and PVCC above POR. The telemetry update rate is 108µs.
R4™ Modulator
The R4™ modulator is an evolutionary step in R3™ technology.
Like R3™, the R4™ modulator is a linear control loop and
variable frequency control during load transients to eliminate
beat frequency oscillation at the switching frequency and
maintains the benefits of current-mode hysteretic controllers.
However, in addition, the R4™ modulator reduces regulator
output impedance and uses accurate referencing to eliminate
the need for a high-gain voltage amplifier in the compensation
loop. The result is a topology that can be tuned to voltage-mode
hysteretic transient speed while maintaining a linear control
model and removes the need for any compensation. This greatly
simplifies the regulator design for customers and reduces
external component cost.
STABILITY
The removal of compensation derives from the R4™ modulator’s
lack of need for high DC gain. In traditional architectures, high DC
gain is achieved with an integrator in the voltage loop. The
integrator introduces a pole in the open-loop transfer function at
low frequencies. That, combined with the double-pole from the
output L/C filter, creates a three pole system that must be
compensated to maintain stability.
Classic control theory requires a single-pole transition through
unity gain to ensure a stable system. Current-mode architectures
(includes peak, peak-valley, current-mode hysteric, R3™ and
R4™) generate a zero at or near the L/C resonant point,
effectively canceling one of the system’s poles. The system still
contains two poles, one of which must be canceled with a zero
before unity gain crossover to achieve stability.
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FN8705.1
March 7, 2016