NCP5010 ON Semiconductor, NCP5010 Datasheet - Page 11

• Manufacturer Part Number: NCP5010
• Description: Boost Converter
• Manufacturer: ON Semiconductor

losses in the coil and must be lower than 1.4 W to limit
excessive voltage drop. In addition, as DCR is reduced,
overall efficiency will improve. Some recommended
inductors include but are not limited to:
TDK VLF4012AT−220MR51
TDK VLP4612T−220MR34
TDK VLP5610T−220MR45
Coilcraft LPO6610−223M
Coilcraft DO1605T−223MX
Coilcraft DT1608C−223
Capacitor Selection
ceramic capacitor type X5R or equivalent should be
selected. For LED driver applications a 1 mF (min) 25 V is
adequate. The NCP5010 can be operated in a voltage mode
configuration (see Figure 34) for applications such as
OLED power. Under these conditions, C
increased to 2.2 mF, 25 V or more to reduce the output
ripple.
low ESR ceramic capacitor near the V
is enough for most applications. However, if the connection
between V
higher
recommended capacitors include but are not limited to:
TDK C1608X5R1E105MT
TDK C2012X5R1E105MT
TDK C1608X5R0J105MT
TDK C2012X5R1E225MT
Murata GRM185R61A105KE36D
Murata GRM188R60J475KE19D
Murata GRM216R61E105KA12D
Short−Circuit Protection
condition is detected. When this event is detected, the
PWM circuitry is disabled and the NMOS power switch is
not turned on. Power will be supplied to the load through
the inductor, rectifier and high side switch. Once V
Finally an acceptable DCR must be selected regarding
To minimize the output ripple, a low ESR multi−layer
The input needs to be bypassed by a X5R or an equivalent
If V
OUT
ceramic capacitor may be needed. Some
IN
is falls below 50% of V
and the battery is too long then a 4.7 mF or
IN
IN
then a short−circuit
pin. A 1 mF, 6.3 V
OUT
can be
http://onsemi.com
OUT
NCP5010
11
reaches 66% of V
normal conditions when the device is enabled by an active
high signal on CTRL, the short circuit condition continues
until the output capacitor is charged by the limited current
up to 66% of V
Overvoltage Protection (OVP)
connection to the White LED string, the converter will
provide current to the C
output will rise rapidly. This could cause damage to the part
if there was not some external clamping Zener clamping
circuit. To eliminate the need for these external
components, the NCP5010 incorporates an OVP circuit
which monitors the output voltage with a resistive divider
network and a comparator and voltage reference. If the
output reaches 22 V (nominal), the OVP circuit will detect
a fault and inhibit PWM operation. This comparator has
1 V of hysteresis so when the load is reconnected and the
voltage drops below 21 V, the PWM operation will resume
automatically. The 22 V OVP threshold allows the use of
25 V ceramic capacitors for the output filter capacitor.
Undervoltage Lock Out (UVLO)
device has a built−in undervoltage lock out (UVLO)
circuit. During power−up, the device will remain disabled
until the input voltage exceeds 2.4 V nominal. This circuit
has 200 mV of hysteresis to provide noise immunity to
transient conditions.
2/3 V
1/2 V
If there is an open load condition such as a loose
To ensure proper operation under all conditions, the
V
Figure 27. Example of the V
OUT
IN
IN
Normal
Running
When Short−Circuit Arises
IN
IN
.
SC
Occurs
, then the PWM circuitry is enabled. In
Short−Circuit Condition
Current limited at 20mA
Converter in Standby
out
capacitor and the voltage at the
OUT
Voltage Behavior
End of Short−Circuit
Detected Converter
Starts Again
T