ADP5022 Analog Devices, ADP5022 Datasheet - Page 16

• Manufacturer Part Number: ADP5022
• Description: Dual 3 MHz, 600 mA Buck Regulator with 150 mA LDO
• Manufacturer: Analog Devices

ADP5022
THEORY OF OPERATION
PGND1
POWER MANAGEMENT UNIT
The ADP5022 is a micro power management units (micro
PMU) combining two step-down (buck) dc-to-dc converters
and a single low dropout linear regulator (LDO). The high
switching frequency and tiny 16-ball WLCSP package allow for
a small power management solution.
To combine these high performance converters and regulators
into the micro PMU, there is a system controller allowing them
to operate together.
Each regulator has a dedicated enable pin. EN1 controls the
activation for Buck1, EN2 controls the activation for Buck2,
and EN3 controls the activation of the LDO. Logic high applied to
the ENx pin turns on the regulator, and a logic low applied to
the ENx pin turns off the regulator. When a regulator is turned
on, the output voltage is controlled through a soft start circuit to
avoid a large inrush current due to the discharged output
capacitors.
VIN1
SW1
EN1
EN2
EN3
CONTROL
ENABLE
ANTISHOOT
THROUGH
DRIVER
PWM
COMP
I
LOW
CURRENT
LIMIT
AND
VDDA VIN3
CONTROL
BUCK1
PWM/
GM ERROR
PSM
AMP
SOFT START
UNDERVOLTAGE
COMP
LOCK OUT
PSM
LDO
CONTROL
Figure 48. Functional Block Diagram
LDO
Rev. C | Page 16 of 28
UNDERVOLTAGE
VOUT1
OSCILLATOR
SHUTDOWN
LOCK OUT
THERMAL
SYSTEM
VOUT2
AGND
The buck regulators can operate in forced PWM mode if the
MODE pin is at a logic high level. In forced PWM mode, the
switching frequency of the two bucks is always constant and
does not change with the load current. If the MODE pin is at a
logic low level, the switching regulators operate in an auto
PWM/ PSM mode. In this mode, the regulators operate at fixed
PWM frequency when the load current is above the power
saving current threshold. When the load current falls below the
power saving current threshold, the regulator in question enters
power saving mode where the switching occurs in bursts. The
burst repetition is a function of the current load and the output
capacitor value. This operating mode reduces the switching
and quiescent current losses. The auto PWM/PSM mode
transition is controlled independently for each buck regulator.
The two bucks operate synchronized to each other.
R1
R2
VOUT3
SOFT START
PSM
COMP
GM ERROR
AMP
MODE
CONTROL
BUCK2
PWM/
PSM
CURRENT
ANTISHOOT
THROUGH
DRIVER
COMP
AND
PWM
I
LOW
LIMIT
ADP5022
VIN2
SW2
PGND2