CXSD62131两个独立的1.5MHz恒定频率电流模式和PWM降压转换器组成2.7V至5.5V输入电压

目录O4U嘉泰姆

1.产品概述                       2.产品特点O4U嘉泰姆
3.应用范围                       4.下载产品资料PDF文档 O4U嘉泰姆
5.产品封装图                     6.电路原理图                   O4U嘉泰姆
7.功能概述                        8.相关产品O4U嘉泰姆

一,产品概述(General Description)   O4U嘉泰姆

  The CXSD62131 CXSD62131A CXSD62131C consists of two independent 1.5MHz constant frequency, current mode, and PWM step-down converters. Each converter integrates a main switch with a synchronous rectifier for high efficiency without an external Schottky diode. The CXSD62131  is ideal for powering portable equipment that runs from a single cell Lithium Ion (Li+) battery. Each converter can supply 1A of load current from a 2.7V to 5.5V input voltage. The output voltage can be regulated as low as 0.6V. The CXSD62131 can also run at 100% duty cycle for low dropout applications.O4U嘉泰姆
二.产品特点(Features)O4U嘉泰姆

1A Output Current on Each ChannelO4U嘉泰姆
2.7V to 5.5V Input Voltage RangeO4U嘉泰姆
1.5MHz Constant Frequency OperationO4U嘉泰姆
Low Dropout Operation at 100% Duty CycleO4U嘉泰姆
Synchronous TopologyO4U嘉泰姆
0.6V Low Reference VoltageO4U嘉泰姆
Current Mode OperationO4U嘉泰姆
Over-Temperature ProtectionO4U嘉泰姆
Over-Current ProtectionO4U嘉泰姆
Up to 94% EfficiencyO4U嘉泰姆
Internally CompensatedO4U嘉泰姆
Lead Free and Green Devices AvailableO4U嘉泰姆
(RoHS Compliant)O4U嘉泰姆
三,应用范围 (Applications)O4U嘉泰姆

TV Tuner/BoxO4U嘉泰姆
Portable InstrumentO4U嘉泰姆
四.下载产品资料PDF文档 O4U嘉泰姆

需要详细的PDF规格书请扫一扫微信联系我们，还可以获得免费样品以及技术支持！O4U嘉泰姆

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五,产品封装图 (Package)O4U嘉泰姆

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六.电路原理图O4U嘉泰姆

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七,功能概述O4U嘉泰姆

Main Control LoopO4U嘉泰姆
The CXSD62131 has dual independent constant frequency,current-mode PWM step-down converters. During nor-O4U嘉泰姆
mal operation, the internal P-channel power MOSFET is turned on each cycle when the oscillator sets an internalO4U嘉泰姆
RS latch and is turned off when an internal comparator (ICMP) resets the latch. The peak inductor current at whichO4U嘉泰姆
ICMP resets the RS latch is controlled by the voltage on the COMP, which is the output of the error amplifierO4U嘉泰姆
(EAMP). An external resistive divider connected between VOUT and ground allows the EAMP to receive an outputO4U嘉泰姆
feedback voltage VFB at FB pin. When the load current increases, it causes a slightly decrease in VFB associatedO4U嘉泰姆
with the 0.6V reference, which in turn causes the COMP voltage to increase until the average inductor currentO4U嘉泰姆
matches the new load current.O4U嘉泰姆
Soft-StartO4U嘉泰姆
Each channel in the CXSD62131 has a built-in soft-start to control the output voltage rise during start-up. During soft-start, an internal ramp, connected to the one of the posi- tive inputs of the error amplifier, raise up to replace the reference voltage (0.6V typical) until the ramp voltage reaches the reference voltage.O4U嘉泰姆
Short Circuit ProtectionO4U嘉泰姆
For each channel, when the output is shortened to the ground, the frequency of the oscillator will be reduced toO4U嘉泰姆
210kHz. This lower frequency allows the inductor current to safely discharge, thereby preventing current runaway.O4U嘉泰姆
The oscillator’s frequency will gradually increase to its designed rate when the feedback voltage on the FB againO4U嘉泰姆
approaches 0.6V.O4U嘉泰姆
Over-Temperature Protection (OTP) O4U嘉泰姆
For each channel, the over-temperature circuit limits the junction temperature of the CXSD62131. When the junctionO4U嘉泰姆
temperature exceeds 150oC, a thermal sensor turns off the power MOSFETs, allowing the channels to cool down.O4U嘉泰姆
The thermal sensor allows the converter to start a soft-start process and to regulate the output voltage againO4U嘉泰姆
after the junction temperature cools by 40ïC. The OTP is designed with a 40ïC hysteresis to lower the averageO4U嘉泰姆
Junction Temperature (TJ) during continuous thermal overload conditions, increasing the lifetime of the device.O4U嘉泰姆
 Enable/ShutdownO4U嘉泰姆
For each channel, driving EN to the ground places the channel in shutdown mode. When in shutdown, the inter-O4U嘉泰姆
nal power MOSFETs are turned off, all internal circuitry shuts down, and the quiescent supply current reduces toO4U嘉泰姆
1μA maximally.O4U嘉泰姆
Automoatic PFM/PWM mode SwitchO4U嘉泰姆
The CXSD62131 is a fixed frequency PWM peak current modulation control step-down converter. At light loads,O4U嘉泰姆
the CXSD62131 will automatically enter in pulse frequency modulation operation to reduce the dominant switchingO4U嘉泰姆
losses. In PFM operation, the inductor current may reach zero or reverse on each pulse. A zero current comparatorO4U嘉泰姆
turns off the N-channel synchronous MOSFET, forcing DCM (Discontinuous Current Mode) operation at lightO4U嘉泰姆
load. These controls get very low quiescent, help to main-tain high efficiency over the complete load range.O4U嘉泰姆
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