Electronic Components Datasheet Search |
|
NCP9001SNT1G Datasheet(PDF) 9 Page - ON Semiconductor |
|
NCP9001SNT1G Datasheet(HTML) 9 Page - ON Semiconductor |
9 / 12 page NCP9001 http://onsemi.com 9 Cycle−by−Cycle Current Limitation From the block diagram (Figure 3), an ILIM comparator is used to realize cycle−by−cycle current limit protection. The comparator compares the LX pin voltage with the reference voltage, which is biased by a constant current. If the inductor current reaches the limit, the ILIM comparator detects the LX voltage falling below the reference voltage and releases the signal to turn off the switch Q1. The cycle−by−cycle current limit is set at 1200 mA (nom). Short Circuit Protection When the output is shorted to ground, the device limits the inductor current. The duty−cycle is minimum and the consumption on the input line is 300 mA (Typ). When the short circuit condition is removed, the device returns to the normal mode of operation. Soft−Start The NCP9001 uses soft−start (300 ms Typ) to limit the inrush current when the device is initially enabled. Soft−start is implemented by gradually increasing the reference voltage until it reaches the full reference voltage. During startup, a pulsed current source charges the internal soft−start capacitor to provide gradually increasing reference voltage. When the voltage across the capacitor ramps up to the nominal reference voltage, the pulsed current source will be switched off and the reference voltage will switch to the regular reference voltage. Shutdown Mode When the EN pin has a voltage applied of less than 0.4 V, the NCP9001 will be disabled. In shutdown mode, the internal reference, oscillator and most of the control circuitries are turned off. Therefore, the typical current consumption will be 0.3 mA (typical value). Applying a voltage above 1.2 V to EN pin will enable the device for normal operation. The typical threshold is around 0.7 V. The device will go through soft−start to normal operation, however, the EN pin should be tied low while the input voltage on VIN pin is rising up. Thermal Shutdown Internal Thermal Shutdown circuitry is provided to protect the integrated circuit in the event that the maximum junction temperature is exceeded. If the junction temperature exceeds 160 _C, the device shuts down. In this mode switch Q1 and Q2 and the control circuits are all turned off. The device restarts in soft−start after the temperature drops below 135 _C. This feature is provided to prevent catastrophic failures from accidental device overheating, and it is not intended as a substitute for proper heatsinking. Low Dropout Operation The NCP9001 offers a low input to output voltage difference. The NCP9001 can operate at 100% duty cycle. In this mode the PMOS (Q1) switches completely on. The minimum input voltage to maintain regulation can be calculated as: VIN(min) + VOUT(max) (eq. 1) ) (IOUT (RDS(on) ) RINDUCTOR)) • VOUT: Output Voltage (Volts) • IOUT: Max Output Current • RDS(on): P−Channel Switch RDS(on) • RINDUCTOR: Inductor Resistance (DCR) |
Similar Part No. - NCP9001SNT1G |
|
Similar Description - NCP9001SNT1G |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |