Datasheet

FUNCTIONAL DEVICE OPERATION
SUPPLIES
Analog Integrated Circuit Device Data
78 Freescale Semiconductor
MC13892
Figure 19. Buck Regulator PWM (Pulse Skipping) Efficiency
DYNAMIC VOLTAGE SCALING
To reduce overall power consumption, processor core voltages can be varied depending on the mode or activity level of the
processor. SW1 and SW2 allow for three different set points with controlled transitions to avoid sudden output voltage changes,
which could cause logic disruptions on their loads. Preset operating points for SW1 and SW2 can be set up for:
• Normal operation: output value selected by SPI bits SWx[4:0]. Voltage transitions initiated by SPI writes to SWx[4:0] are
governed by the same DVS stepping rate that is programmed for DVSx pin initiated transitions.
• DVS: output can be higher or lower than normal operation for tailoring to application requirements. Configured by SPI bits
SWxDVS[4:0] and controlled by a DVSx pin transition.
• Standby (Deep Sleep): can be higher or lower than normal operation, but is typically selected to be the lowest state retention
voltage of a given process. Set by SPI bits SWxSTBY[4:0] and controlled by a Standby event (STANDBY logically anded with
STANDBYSEC). Voltage transitions initiated by Standby are governed by the same DVS stepping that is programmed for
DVSx pin initiated transitions.
The following tables summarize the set point control and DVS time stepping applied to SW1 and SW2.
SW1 P WM Pu lse S kip pi ng mo de E fficiency Vo ut = 0,725 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 10203040 5060 7080 90100
Ilo a d (m A)
E f fic ien cy (% )
V i n = 3 ,00 0 V
V i n = 3 ,60 0 V
V i n = 4 ,65 0 V
SW1 PWM Pulse Ski pping mo de Efficiency Vo ut = 0,725 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 50 1 00 150 200 25 0 300 35 0 4 00 450 50 0 55 0 6 00 650 70 0 7 50 800 85 0 90 0 9 50 10 0
0
105
0
Il oa d (m A)
E f fic ien cy (%
)
V i n = 3,0 00 V
V i n = 3,6 00 V
V i n = 4,6 50 V
SW2 P WM Pu lse S kip pi ng mo de E fficiency Vo ut = 1.250 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 10203040 5060 7080 90100
Ilo a d (m A)
E f fic ien cy (%
)
V i n = 3 ,00 0 V
V i n = 3 ,60 0 V
V i n = 4 ,65 0 V
SW2 PWM Pu lse Skip pin g mode Efficiency Vou t = 1.250 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 50 1 00 1 50 20 0 25 0 300 350 4 00 4 50 50 0 55 0 600 650 7 00 7 50 80 0 85 0 900
Ilo a d (m A)
E f fic ien cy (%
)
V i n = 3, 000 V
V i n = 3, 600 V
V i n = 4, 650 V
SW4 P WM Pu lse S kip pi ng mo de E fficiency Vo ut = 1.800 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 10203040 5060 7080 90100
Ilo a d (m A)
E f fic ien cy (% )
V i n = 3 ,00 0 V
V i n = 3 ,60 0 V
V i n = 4 ,65 0 V
SW4 PWM Pulse Ski pping mo de Efficiency Vo ut = 1.800 V
0%
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %
100 %
0 50 1 00 1 50 20 0 2 50 30 0 35 0 400 450 5 00 5 50 60 0 65 0 700 750 8 00 850 9 00
Il oa d (m A)
E f fic ien cy (% )
V i n = 3,0 00 V
V i n = 3,6 00 V
V i n = 4,6 50 V