CS5159

http://onsemi.com

9

M 1.00 μs

Trace 1− Regulator Output Voltage (10 mV/div.)

Trace 2− Inductor Switching Node (5.0 V/div.)

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.

For best transient response, a combination of a number of

high frequency and bulk output capacitors are usually used.

If the maximum on time is exceeded while responding to

a sudden increase in load current, a normal off time occurs

to prevent saturation of the output inductor.

Figure 9. CS5159 Demonstration Board Response to

a 0.5 to 13 A Load Pulse (Output Set for 2.8 V)

Trace 2− Regulator Output Voltage (20 V/div.)

Trace 1− Regulator Output Voltage (1.0 V/div.)

Figure 10. CS5159 Demonstration Board Response to

13 A Load Turn On (Output Set for 2.8 V). Upon

Immediately Connects the Inductor to the Input

Voltage, Providing 100% Duty Cycle. Regulation is

Achieved in Less Than 20 ms

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.)

Figure 11. CS5159 Demonstration Board Response to

Topology Immediately Connects Inductor to Ground,

Providing 0% Duty Cycle. Regulation is Achieved in

Less Than 10 ms

Trace 3− Output Current (13 to 0,5 Amps) (10 A/div.)

Trace 2− Inductor Switching Node (5.0 V/div.)

Trace 1− Regulator Output Voltage (100 mV/div.)

PROTECTION AND MONITORING FEATURES

To maintain predictable startup and shutdown

prevent the part from operating below 3.75 V minimum

and guarantees a 3.70 V minimum shutdown threshold.