cs5157h ON Semiconductor, cs5157h Datasheet - Page 9

• Manufacturer Part Number: cs5157h
• Description: Cpu 5-bit Synchronous Buck Controller
• Manufacturer: ON Semiconductor

Transient Response
provides unprecedented transient response to changes in
input voltage or output current. Pulse by pulse adjustment of
duty cycle is provided to quickly ramp the inductor current
to the required level. Since the inductor current cannot be
changed instantaneously, regulation is maintained by the
output capacitor(s) during the time required to slew the
inductor current.
high frequency and bulk output capacitors are usually used.
a sudden increase in load current, a normal off time occurs
to prevent saturation of the output inductor.
Figure 9. CS5157H Demonstration Board Response
The CS5157H V
For best transient response, a combination of a number of
If the maximum on time is exceeded while responding to
Trace 1− Regulator Output Voltage (100 mV/div.)
Trace 2− Regulator Output Voltage (10 A/div.)
to a 0.5 to 13 A Load Pulse (Output Set for 2.8 V)
Trace 1− Regulator Output Voltage (10 mV/div.)
Trace 2− Inductor Switching Node (5.0 V/div.)
Figure 8. Peak−to−Peak Ripple on V
I
OUT
2
= 13 A (Heavy Load)
control loop’s 100 ns reaction time
M 1.00 ms
OUT
= 2.8 V,
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CS5157H
9
V
characteristics an internal V
prevent the part from operating below 3.75 V minimum
startup. The V
and guarantees a 3.70 V minimum shutdown threshold.
Figure 10. CS5157H Demonstration Board Response to
Figure 11. CS5157H Demonstration Board Response to
Topology Immediately Connects Inductor to Ground,
CC1
13 A Load Turn Off (Output Set for 2.8 V). V
Completing a Normal Off Time, The V
Providing 0% Duty Cycle. Regulation is Achieved in
To
PROTECTION AND MONITORING FEATURES
Voltage, Providing 100% Duty Cycle. Regulation is
Trace 1− Regulator Output Voltage (100 mV/div.)
Trace 2− Inductor Switching Node (5.0 V/div.)
Trace 3− Output Current (0.5 to 13 Amps) (10 A/div.)
Immediately Connects the Inductor to the Input
13 A Load Turn On (Output Set for 2.8 V). Upon
Trace 1− Regulator Output Voltage (100 mV/div.)
Trace 2− Inductor Switching Node (5.0 V/div.)
Trace 3− Output Current (13 to 0,5 Amps) (10 A/div.)
Monitor
maintain
Achieved in Less Than 20 ms
CC1
monitor comparator provides hysteresis
predictable
Less Than 10 ms
CC1
startup
monitor circuit is used to
2
and
Control Loop
2
Control
shutdown