ADP-I2C-USB-Z View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
ADP-I2C-USB-Z Datasheet PDF : 108 Pages
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ADP1051
Data Sheet
When using high-side current sensing, as shown in Figure 27, the
current sources are 1.915 mA. Therefore, the required resistor value
is (VOUT − 1.12 V)/1.915 mA. If VOUT = 12 V, 5.62 kΩ resistors are
required.
VOUT
CS2+
CS2–
12 BITS
ADC
1.915mA
1.915mA
ADP1051
Figure 27. CS2 High-Side Resistive Current Sense
The ADC samples at a frequency of 1.56 MHz, and the reading
is averaged in an asynchronous fashion. This reading is used to
determine actions on faults, such as the IOUT OC fault, with an
average rate of 82 µs (seven bits) or 328 µs (nine bits), which is set
by Register 0xFE1B[4]. The ADP1051 also reports an output current
reading in the READ_IOUT command (Register 0x8C), with
an average rate of 10 ms, 52 ms, 105 ms, or 210 ms, as set by
Register 0xFE65[1:0].
Various limits and response actions can be set for CS2, such as the
IOUT_OC_FAULT_LIMIT command (Register 0x46) and the
IOUT_OC_FAULT_RESPONSE (Register 0x47) command. These
limits and responses are described in the PMBus Command Set
and Current Sense and Limit Setting Registers section.
SOFT START AND SHUTDOWN
On/Off Control
The OPERATION command (Register 0x01) and the ON_OFF_
CONFIG command (Register 0x02) control the power-on and
power-off behavior of the ADP1051. The OPERATION command
turns the ADP1051 on and off in conjunction with input from the
CTRL pin (Pin 16). The combination of the CTRL pin input and
serial bus commands required to turn the ADP1051 on and off is
configured by the ON_OFF_CONFIG command. When the
ADP1051 is commanded to turn on, the power supply on (PSON)
signal is enabled, and the ADP1051 follows the soft start procedure to
begin the power conversion.
Soft Start
After VDD power-up and initialization, the PSON signal is enabled
when the ADP1051 is commanded to turn on. The controller waits
for a user specified turn-on delay (TON_DELAY, Register 0x60)
before initiating this output voltage soft start ramp. The soft start is
then performed by actively regulating the output voltage and digitally
ramping up the target voltage to the commanded voltage setpoint.
The rise time of the voltage ramp is programmed, using the TON_
RISE command (Register 0x61), to minimize the inrush currents
associated with the start-up voltage ramp. A nonzero pre-biased
voltage results in a longer turn-on delay and shorter rise time.
CTRL
PIN
REG 0x02[1]
ON
OFF
IMMEDIATE
OFF
DELAY OFF
REG 0x02[0]
OPERATION
(SOFTWARE)
REG 0x01[7:6]
IMMEDIATE
OFF
ON
DELAY OFF
ALWAYS ON
VOUT COMMAND
VOUT MARGIN LOW
ON/OFF
OPERATION
REG 0x02[4:2]
VOUT MARGIN HIGH
REG 0x01[5:4]
Figure 28. On/Off Control Diagram
Rev. B | Page 24 of 108
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