NXP Semiconductors
PF4210
14-channel power management integrated circuit (PMIC) for audio/video applications
10.4.4.1 Current limit
Each buck regulator has a programmable current limit. In an overcurrent condition,
the current is limited cycle-by-cycle. If the current limit condition persists for more than
8.0 ms, a fault interrupt is generated.
10.4.4.2 General control
To improve system efficiency the buck regulators can operate in different switching
modes. Changing between switching modes can occur by any of the following means:
I2C programming, exiting/entering the standby mode, exiting/entering sleep mode, and
load current variation.
Available switching modes for buck regulators are presented in Table 28.
Table 28.ꢀSwitching mode description
Mode
OFF
Description
The regulator is switched off and the output voltage is discharged.
PFM
In this mode, the regulator is always in PFM mode, which is useful at light loads for
optimized efficiency.
PWM
APS
In this mode, the regulator is always in PWM mode operation regardless of load
conditions.
In this mode, the regulator moves automatically between pulse skipping mode and
PWM mode depending on load conditions.
During soft start of the buck regulators, the controller transitions through the PFM, APS,
and PWM switching modes. 3.0 ms (typical) after the output voltage reaches regulation,
the controller transitions to the selected switching mode. Depending on the particular
switching mode selected, additional ripple is observed on the output voltage rail as the
controller transitions between switching modes.
Table 29 summarizes the buck regulator programmability for normal and standby modes.
Table 29.ꢀRegulator mode control
SWxMODE[3:0]
0000
Normal mode
Off
Standby mode
Off
0001
PWM
Off
0010
Reserved
PFM
Reserved
Off
0011
0100
APS
Off
0101
PWM
PWM
0110
PWM
APS
0111
Reserved
APS
Reserved
APS
1000 (by default)
1001
Reserved
Reserved
Reserved
APS
Reserved
Reserved
Reserved
PFM
1010
1011
1100
PF4210
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© NXP B.V. 2018. All rights reserved.
Data sheet: technical data
Rev. 2.0 — 14 November 2018
33 / 137
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