ADP5140WACCZ-R7 datasheet(35/128 Pages) AD

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Data Sheet

ADP5140

Rev. 0 | Page 35 of 128

output voltage of the DVS ranges from 0.8 V to 1.4 V for

BUCK1 with a fixed 10 mV step and from 0.55 V to 1.20 V for

BUCK4 with a fixed 12.5 mV step.

NEW CODE

ORIGINAL CODE

INTERVAL

STEP

ORIGINAL VOUT

NEW VOUT

TRANSITION PERIOD

Figure 79. Dynamic Voltage Scaling

Table 18. DVS Interval Options

BUCK1_INTERVAL,

Bits[1:0]

BUCK4_INTERVAL,

Bits[1:0]

Interval Time (µs)

00 (Default)

00 (default)

Buck Regulator Current Limit

The buck regulators have a peak current-limit protection

circuit to prevent current runaway. When the peak inductor

current reaches the high-side MOSFET current-limit threshold,

the high-side MOSFET turns off and the low-side MOSFET

turns on. When the low-side MOSFET turns on, the internal

circuit continues monitoring the current flowing through the

low-side MOSFET. At the end of each clock cycle, if the low-

side MOSFET source current is greater than the low-side

source current-limit threshold, the high-side MOSFET remains

off and the low-side MOSFET remains on for the next cycle.

The high-side MOSFET turns on again when the low-side

source current is below the low-side source current-limit

threshold at the start of a cycle.

The current limitation induces a duty cycle reduction, leads to

output voltage drops, and can cause an undervoltage condition.

The current limitation does not turn off the buck regulator.

The low-side MOSFET in the buck regulator can sink a current

from the load. If the low-side sink current limit is exceeded,

both the low-side and high-side MOSFETs turn off until the

next cycle starts.

Undervoltage and Overvoltage Protection for Buck

Regulator Output Voltages

A window comparator monitors the VOUTx of each buck regulator

through each regulator feedback pin (FBx). If the voltage on the

feedback pin is outside of the warning or fault window, an output

voltage warning or fault event is detected. The window

comparator uses a dedicated reference for safety consideration.

The warning or fault threshold of the undervoltage protection and

overvoltage protection is programmable through the SPI. Refer

to the Feedback Voltage Monitor section for more information.

Buck Regulator Local Temperature Warning

Each buck regulator has a local temperature monitor that

provides thermal warning protection. If the local temperature

of the buck regulator is higher than the overtemperature

threshold, an overtemperature warning event occurs. This

warning event is reported in the OT_STATUS register and

OT_LATCH register. The buck regulator still functions when

an overtemperature warning occurs.

SYNCHRONOUS BOOST REGULATOR

The boost regulator integrates both the main FET and the

synchronous FET and runs at a fixed 2.2 MHz switching

frequency in phase with BUCK1. The output voltage of the

boost regulator is fixed at 5 V and provides a load current of up

to 400 mA. The boost regulator has the true shutdown feature

that allows the input voltage and the output voltage of the boost

regulator to be isolated when the boost regulator is disabled.

Boost Regulator Current Limit

The boost regulator integrates the cycle-by-cycle current-limit

circuit to prevent current runaway. When the inductor peak

current exceeds the current-limit threshold of the main FET,

the main FET turns off and the synchronous FET turns on. The

synchronous FET also has negative current protection. If the

negative current flowing through the synchronous FET exceeds

the negative current-limit threshold, both the main FET and

the synchronous FET turn off until the next cycle.

The current-limit feature induces a duty cycle reduction and

leads to output voltage drops that can cause an undervoltage

condition. The current-limit feature does not turn the boost

regulator off.

Undervoltage and Overvoltage Protection for Boost

Regulator Output Voltage

A window comparator monitors the output voltage of the boost

regulator through the FB12 pin. If the voltage on the FB12 pin

is outside of the warning or fault window, an output voltage

warning or fault event is detected. The window comparator

uses a dedicated reference for safety consideration.

The warning or fault threshold is programmable through the

SPI. Refer to the Feedback Voltage Monitor section for more

information.

Boost Regulator Local Temperature Warning

A local temperature monitor is integrated into the boost

regulator to provide thermal warning protection. If the local

temperature of the boost regulator is higher than the

overtemperature threshold, an overtemperature warning event

occurs. This warning event is reported in the OT_STATUS

functions when an overtemperature warning occurs.

ADP5140WACCZ-R7 数据表(PDF) 35 Page - Analog Devices

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