PT1115-高效率PWM开关降压器

PT1115-1.5A Constant Voltage and Constant Current Buck with Cable Resistance Compensation PDF文档下载

PT1115是高效率的脉冲宽度调制（PWM）开关模式降压转换器，实现输出恒压（CV）和恒流（CC）功能； PT1115输入电压最高到35V；在CC模式下，通过取样电阻设计输出1.5A的电流精度小于±10％；在CV模式下，输出电压控制在5V±2％；PT1115具有最大300mV的线性补偿，补偿值是基于外部电容和线缆电阻取值；PT1115的开关频率通过外部电阻设定； PT1115具有过压，欠压锁定，对地短路，峰值电流限制和过温关断保护功能；PT1115封装有ESOP-8和QFN16。

GENERAL DESCRIPTION

The PT1115 is a low cost, high efficiency pulse-width modulated (PWM) switching mode buck converter with both constant voltage (CV) and constant current (CC) functions. The input voltage of PT1115 can be as high as 35V at which the over-voltage protection is triggered. The VIN pin is capable of sustaining 48V that further improves the reliability of the PT1115 under the conditions of hot swap and surging voltages. In the CC mode, the output current variation is less than ±10% of the nominal value which can be set up to 1.5A by the current sensing resistor. In the CV mode, the output voltage is controlled within ±2% of 5V. In the PT1115, output cable wire resistance compensation is implemented to offset up to 300mV voltage drop along the cable. The amount of compensation can be programmed by an external capacitor based on the cable resistance.
The switching frequency of the PT1115 can also be programmed by an external resistor. With user optimized frequency, together with the inherent small output ripple voltage and spread spectrum technique, the PT1115 based system can achieve great EMI performance. The PT1115 provides protections against over-voltage, under-voltage lockout, short-ground, peak current limit, and over-temperature shutdown to guarantee safe applications under extreme conditions.
The PT1115 is available in ESOP-8 and QFN16 packages

FEATURES
7.0~35V operating input voltage range
50k~250kHz switching frequency programmed by an external resistor.
PWM control
± 10% output current accuracy in the CC mode
0.5~ 1.5A output current set by a small current sensing resistor
± 2% output voltage accuracy in the CV mode
Cable wire resistance compensation.
Input and output over voltage protections (OVP)
Short-ground protection
Cycle-by-cycle switching peak current limit
Soft start for power-up
160oC over temperature shutdown
under-voltage lockout (UVLO)
Frequency dithering to reduce EMI
60mW no load power consumption
ESOP-8 and QFN16 （ 4* 4mm ） package
RoHS & HF(Halogen free) compliant

APPLICATIONS
Automobile chargers
Step-down DC/DC conversion
LCD TVs
Larger current battery charging adaptors