ncp3064b ON Semiconductor, ncp3064b Datasheet - Page 16

• Manufacturer Part Number: ncp3064b
• Description: 1.5 A, Step-up/down/ Inverting Switching Regulator With On/off Function
• Manufacturer: ON Semiconductor

Schematic shows typical configuration with external PMOS
transistor. Resistor R7 connected between timing capacitor
TC Pin and SWE Pin provides a pulse feedback voltage.
The pulse feedback approach increases the operating
ffrequency by up to 50%. Figure 28, Oscillator Frequency
vs. Timing Capacitor with Pulse Feedback, shows the
impact to the oscillator frequency at buck converter for V
= 12 V and V
R
waveforms with constant operating frequency which results
in lower ripple voltage and improved efficiency.
7
The picture in Figure 24. Typical Buck Application
= 10 kW. It also creates more regular switching
ON/OFF
V
IN
out
+
= 3.3 V with pulse feedback resistor
Figure 28. Oscillator Frequency vs. Timing Capacitor with Pulse Feedback
R
sense
450
400
350
300
250
200
150
100
50
0
0
Figure 29. ON/OFF Serial Resistor Connection
Without Pulse
Feedback
2
R15
10k
R
4
TIMING CAPACITANCE (nF)
With Pulse
Feedback
6
http://onsemi.com
8
in
10
16
12
voltage and the power supply is not connected to Vcc pin at
the same time, then it is recommended to limit ON/OFF
current by resistor with value 10 kW to protect the NCP3064
device. This situation is mentioned in Figure 29, ON/OFF
Serial Resistor Connection.
200 mV to higher value, but the TTL logic compatibility is
kept in full range of input voltage and operating temperature
range.
If the application allows ON/OFF pin to be biased by
This resistor shifts the ON/OFF threshold by about
14
16
ON/OFF
Ipk
V
FB
CC
18
20
NCP3064
22
IC1
SWC
SWE
GND
CT