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目录zDb嘉泰姆

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

一,产品概述(General Description)     zDb嘉泰姆

  The CXSD62129 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 CXSD62129 is ideal for powering portable equipment that runs from a single cell Lithium Ion (Li+) battery. Each converter can supply 1A of loadzDb嘉泰姆
current from a 2.7V to 5.5V input voltage. The output volt age can be regulated as low as 0.6V. The CXSD62129 can also run at 100% duty cycle for low dropout applications.zDb嘉泰姆
二.产品特点(Features)zDb嘉泰姆

1A Output Current on Each ChannelzDb嘉泰姆
2.7V to 5.5V Input Voltage RangezDb嘉泰姆
1.5MHz Constant Frequency OperationzDb嘉泰姆
Low Dropout Operation at 100% Duty CyclezDb嘉泰姆
Synchronous TopologyzDb嘉泰姆
0.6V Low Reference VoltagezDb嘉泰姆
Current Mode OperationzDb嘉泰姆
Over-Temperature ProtectionzDb嘉泰姆
Over-Current ProtectionzDb嘉泰姆
Up to 94% EfficiencyzDb嘉泰姆
Internally CompensatedzDb嘉泰姆
Lead Free and Green Devices AvailablezDb嘉泰姆
(RoHS Compliant)zDb嘉泰姆
三,应用范围 (Applications)zDb嘉泰姆

TV Tuner/BoxzDb嘉泰姆
Portable InstrumentzDb嘉泰姆
四.下载产品资料PDF文档 zDb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！zDb嘉泰姆

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五,产品封装图 (Package)zDb嘉泰姆

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六.电路原理图zDb嘉泰姆

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七,功能概述zDb嘉泰姆

Main Control LoopzDb嘉泰姆

The CXSD62129 has dual independent constant frequency,current-mode PWM step-down converters. During nor-zDb嘉泰姆
mal operation, the internal P-channel power MOSFET is turned on each cycle when the oscillator sets an internalzDb嘉泰姆
RS latch and is turned off when an internal comparator (ICMP) resets the latch. The peak inductor current at whichzDb嘉泰姆
ICMP resets the RS latch is controlled by the voltage on the COMP, which is the output of the error amplifierzDb嘉泰姆
(EAMP). An external resistive divider connected between VOUT and ground allows the EAMP to receive an outputzDb嘉泰姆
feedback voltage VFB at FB pin. When the load current increases, it causes a slightly decrease in VFB associatedzDb嘉泰姆
with the 0.6V reference, which in turn causes the COMP voltage to increase until the average inductor currentzDb嘉泰姆
matches the new load current.zDb嘉泰姆
Soft-StartzDb嘉泰姆
Each channel in the CXSD62129 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.zDb嘉泰姆
Short Circuit ProtectionzDb嘉泰姆
For each channel, when the output is shortened to the ground, the frequency of the oscillator will be reduced tozDb嘉泰姆
210kHz. This lower frequency allows the inductor current to safely discharge, thereby preventing current runaway.zDb嘉泰姆
The oscillator’s frequency will gradually increase to its designed rate when the feedback voltage on the FB againzDb嘉泰姆
approaches 0.6V.zDb嘉泰姆
Over-Temperature Protection (OTP)zDb嘉泰姆
For each channel, the over-temperature circuit limits the junction temperature of the CXSD62129. When the junction temperature exceeds 150oC, a thermal sensor turns off the power MOSFETs, allowing the channels to cool down.The thermal sensor allows the converter to start a soft- start process and to regulate the output voltage againzDb嘉泰姆
after the junction temperature cools by 40ïC. The OTP is designed with a 40ïC hysteresis to lower the averagezDb嘉泰姆
Junction Temperature (TJ) during continuous thermal overload conditions, increasing the lifetime of the device. zDb嘉泰姆
Enable/ShutdownzDb嘉泰姆
For each channel, driving EN to the ground places the channel in shutdown mode. When in shutdown, the inter-zDb嘉泰姆
nal power MOSFETs are turned off, all internal circuitry shuts down, and the quiescent supply current reduces tozDb嘉泰姆
1μA maximally. zDb嘉泰姆
Automoatic PFM/PWM mode SwitchzDb嘉泰姆
The CXSD62129 is a fixed frequency PWM peak current modulation control step-down converter. At light loads,zDb嘉泰姆
the CXSD62129 will automatically enter in pulse frequency modulation operation to reduce the dominant switchingzDb嘉泰姆
losses. In PFM operation, the inductor current may reach zero or reverse on each pulse. A zero current comparatorzDb嘉泰姆
turns off the N-channel synchronous MOSFET, forcing DCM (Discontinuous Current Mode) operation at lightzDb嘉泰姆
load. These controls get very low quiescent, help to main- tain high efficiency over the complete load range.zDb嘉泰姆

八,相关产品                 更多同类产品.......zDb嘉泰姆

◀ Previous:3A 5V 2MHz Synchronous Buck Converter CXSD62128/A/B is a 3A synchronous buck converter with integrated 110mW power MOSFETs. The CXSD62128/A/B is designed with a current-mode control scheme;

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Next▶:CXSD62129A consists of two independent 1.5MHz con- stant frequency current mode and PWM step-down converters. Each converter integrates a main switch with a synchronous rectifier