目录uvs嘉泰姆

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

一,产品概述(General Description)     uvs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 loaduvs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.uvs嘉泰姆
二.产品特点(Features)uvs嘉泰姆

1A Output Current on Each Channeluvs嘉泰姆
2.7V to 5.5V Input Voltage Rangeuvs嘉泰姆
1.5MHz Constant Frequency Operationuvs嘉泰姆
Low Dropout Operation at 100% Duty Cycleuvs嘉泰姆
Synchronous Topologyuvs嘉泰姆
0.6V Low Reference Voltageuvs嘉泰姆
Current Mode Operationuvs嘉泰姆
Over-Temperature Protectionuvs嘉泰姆
Over-Current Protectionuvs嘉泰姆
Up to 94% Efficiencyuvs嘉泰姆
Internally Compensateduvs嘉泰姆
Lead Free and Green Devices Availableuvs嘉泰姆
(RoHS Compliant)uvs嘉泰姆
三,应用范围 (Applications)uvs嘉泰姆

TV Tuner/Boxuvs嘉泰姆
Portable Instrumentuvs嘉泰姆
四.下载产品资料PDF文档 uvs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！uvs嘉泰姆

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五,产品封装图 (Package)uvs嘉泰姆

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六.电路原理图uvs嘉泰姆

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七,功能概述uvs嘉泰姆

Main Control Loopuvs嘉泰姆

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

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