PAC5253
Power Application Controller
9V, or 12V by the microcontroller after initialization.1 When VP is lower than the target regulation voltage, the internal
feedback control circuitry causes the inductor current to increase to raise VP. Conversely, when VP is higher than the
regulation voltage, the feedback loop control causes the inductor current to decrease to lower VP. The feedback loop is
internally stabilized. The output current capability of the switching supply is determined by the external current sense
resistor. In the high-side current sense buck mode, the inductor current signal is sensed differentially between the CSM pin
and VP, and has a peak current limit threshold of 0.26V. In the low-side current sense flyback or boost mode, the inductor
current signal is sensed differentially between the CSM pin and VSS, and has a peak current limit threshold of 1V.
The MMSS controller is flexible and configurable as a buck, flyback, or boost converter. Input sources include battery
supply for buck mode (Figure 10-2), and AC line supply voltage range for ultra-high-voltage buck mode (Figure 10-3),
AC/DC flyback mode (Figure 10-4). The MMSS controller operational mode is determined by external configuration and
register setting from the microcontroller after power up. It can operate in either high-side or low-side current sense mode,
and does not require external feedback loop compensation circuitry. For optional extended application range, the MMSS
also incorporates additional digital control by the microcontroller to add accurate computations for outer feedback loop
control such as power factor correction and accurate current control.
Figure 10-2. Buck Mode
VHM
DRM
V
IN
PAC525x3x
V
(15V default)
P
CSM
VP
Figure 10-3. Ultra-High-Voltage Buck Mode
VHM
V
(120V/230V)
AC
PAC521503
DRM
V
(15V default)
P
CSM
VP
1
Note that on any device with ultra-high voltage drivers (PAC525X), it is invalid to set VP to less than 12V.
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Rev 1.24‒March 3, 2018
ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
