• "

Ordering

1.产品概述                       2.产品特点XwI嘉泰姆
3.应用范围                       4.下载产品资料PDF文档 XwI嘉泰姆
5.产品封装图                     6.电路原理图                   XwI嘉泰姆
7.功能概述                        8.相关产品XwI嘉泰姆

七,功能概述XwI嘉泰姆

Main Control LoopXwI嘉泰姆
The CXSD62144 is a constant frequency current mode switching regulator. During normal operation, the inter-XwI嘉泰姆
nal N-channel power MOSFET is turned on each cycle when the oscillator sets an internal RS latch and wouldXwI嘉泰姆
be turned off when an internal current comparator (ICMP) resets the latch. The peak inductor current at which ICMPXwI嘉泰姆
resets the RS latch is controlled by the voltage on the COMP pin, which is the output of the error amplifierXwI嘉泰姆
(EAMP). An external resistive divider connected between VOUT and ground allows the EAMP to receive an outputXwI嘉泰姆
feedback voltage VFB at FB pin. When the load current increases, it causes a slight decrease in VFB relative toXwI嘉泰姆
the 0.925V reference, which in turn causes the COMP voltage to increase until the average inductor currentXwI嘉泰姆
matches the new load current.XwI嘉泰姆
VIN Power-On-Reset (POR) and EN Under-voltage LockoutXwI嘉泰姆
The CXSD62144 keep monitoring the voltage on VIN pin to prevent wrong logic operations which may occur whenXwI嘉泰姆
VIN voltage is not high enough for the internal control circuitry to operate. The VIN POR has a rising thresholdXwI嘉泰姆
of 4.05V (typical) with 0.3V of hysteresis.XwI嘉泰姆
An external under-voltage lockout (UVLO) is sensed atthe EN pin. The EN UVLO has a rising threshold of 2.5VXwI嘉泰姆
with 0.2V of hysteresis. The EN pin should be connected a resistor divider from VIN to EN .After the VIN and ENXwI嘉泰姆
voltages exceed their respective voltage thresholds, the IC starts a start-up process and then ramps up the outputXwI嘉泰姆
voltage to the setting of output voltage.XwI嘉泰姆
Over-Temperature Protection (OTP)XwI嘉泰姆
The over-temperature circuit limits the junction tempera-ture of the CXSD62144 When the junction temperature ex-XwI嘉泰姆
ceeds TJ =+160oC, a thermal sensor turns off the power MOSFET, allowing the device to cool down. The thermalXwI嘉泰姆
sensor allows the converter to start a start-up process and regulate the output voltage again after the junctionXwI嘉泰姆
temperature cools by 50oC.XwI嘉泰姆
The OTP designed with a 50 oC hysteresis lowers the average T J during c ontinuous thermal overload conditions,XwI嘉泰姆
increasing life time of the IC.XwI嘉泰姆
Enable/ShutdownXwI嘉泰姆
Driving EN to ground places the CXSD62144 in shutdown.When in shutdown, the internal N-Channel power MOSFET turns off, all internal circuitry shuts down and the quies-cent supply current reduces to 0.3μA.XwI嘉泰姆
Current-Limit ProtectionXwI嘉泰姆
The CXSD62144 monitors the output current, flowing through the N-Channel power MOSFET, and limits theXwI嘉泰姆
IC from damages during overload, short-circuit and over-voltage conditions.XwI嘉泰姆
Frequency FoldbackXwI嘉泰姆
The foldback frequency is controlled by the FB voltage.When the FB pin voltage is under 0.6V, the frequency ofXwI嘉泰姆
the oscillator will be reduced to 110kHz. This lower fre-quency allows the inductor current to safely discharge,XwI嘉泰姆
thereby preventing current runaway. The oscillator’s fre-quency will switch to its designed rate when the feedbackXwI嘉泰姆
voltage on FB rises above the rising frequency foldback threshold (0.6V, typical) again.XwI嘉泰姆
Over-Voltage ProtectionXwI嘉泰姆
The over-voltage function monitors the output voltage by FB pin. When the FB voltage increase over 120% of theXwI嘉泰姆
reference voltage, the over-voltage protection compara-tor will force the high-and low-side MOSFET gate driverXwI嘉泰姆
off. As soon as the output voltage is within regulation, the OVP comparator is disengaged. The chip will restore itsXwI嘉泰姆
normal operation.XwI嘉泰姆
八,相关产品         更多同类产品.......XwI嘉泰姆

◀ Previous:CXSD62144 CXSD62145 CXSD62146 CXSD62147 a 3A synchronous buck converter with integrated 110mΩ power MOSFETs.

Back to top

Next▶:CXSD62144 CXSD62145 CXSD62146 CXSD62147 a 3A synchronous buck converter with integrated 110mΩ power MOSFETs.