PDF《PS25A》

PS25A Version : A.

005 Issue Date : 2012/03/28 File Name : SP-PS25A-A.005.doc Total Pages :

11 3-Channel Secondary Monitoring IC 新竹市科学园区展业一?

9 号7?之

1 SILICON TOUCH TECHNOLOGY INC. 9-7F-1, Prosperity Road I, Science Based Industrial Park, Hsin-Chu, Taiwan 300, R.O.C. Tel:886-3-5645656 Fax:886-3-5645626 3-Channel Secondary Monitoring IC Version:A.005 Page

1 未经授权而迳予重制、复制、使用或公开本文件,?为人得被追究侵权之相关民刑事责任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PS25A PS25A 3-Channel Secondary Monitoring IC General Description PS25A is specially designed for switching power supply system. Four important functions of PS25A are the followings: over-voltage protection, over-current protection, under-voltage protection and power good signal generating. OVP/UVP (Over-Voltage/Under-Voltage Protection) monitors triple 12V to protect our power supply and PC, FPO/ goes to high when one of these supply voltages exceeds their normal operation voltage range. OCP (Over Current Protection) monitors IS12A, IS12B, IS12C input current sense. An adjustable over-current condition composed of Iref and protection current range resistor helps users design OCP easily. An additional protection input pin provides the flexibility for design protection circuit. Power good signal generating notifies personal computer when power supply is ready or power supply is going to shutdown, therefore it can provide a reliable power supply environment. Features ? Over/Under-voltage protection and lock out ? Over-current protection and lock out ? Additional protection input ? Fault protection output with open drain output stage ? Open drain power good output signal for power good input ? Built-in 300mS power good delay ? AC on 75ms delay for UV/OC protection ? 38mS PSON/ control de-bounce ? Wide power supply range (3.8V~16V) ? Special care for AC power off 3-Channel Secondary Monitoring IC Version:A.005 Page

2 未经授权而迳予重制、复制、使用或公开本文件,?为人得被追究侵权之相关民刑事责任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PS25A Block Diagram VS12B R1 R2 R3 Vref Vref

12 OV

12 UV Band-Gap Reference Power On Reset Clock Generator 38mS De-bounce Constant Current Source Iref FPO/ PGI PGO RI GND POR Vref CLK 73uS De-bounce H: 300mS L : 4.5uS delay 1MΩ H: 75mS L : 4.5uS delay 1.25V VCCI S Q R 1MΩ H: 4mS L : 4.5uS delay VS12A

12 OV

12 UV R1 R2 R3 Vref Vref 1.25V Pext Internal Power VCCI = 4V H: 20mS L : 4.5uS delay IS12A Iref X

8 12 OC VCCI Step Down to near 2.5V IS12B Iref X

8 12 OC VCCI Step Down to near 2.5V 1.25V 3mS delay VCC VCC 3mS delay 14uS delay PGI Selection PSON/ VCC 30KΩ Vref VCCI 90KΩ 4.5V 2KΩ VS12C R1 R2 R3 Vref Vref IS12C Iref X

8 Step Down to near 2.5V

12 OC VCCI

12 UV

12 OV 3-Channel Secondary Monitoring IC Version:A.005 Page

3 未经授权而迳予重制、复制、使用或公开本文件,?为人得被追究侵权之相关民刑事责任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PS25A Timing Chart Td1 Tb1 Td3 Td2 FPO/ PSON/ PGI Vcc PGO UVP/OVP/OCP Pext protect PSON/ turn on AC turn on PSON/ turn off PSON/ turn on AC turn off IS12A VS12B IS12B VS12C IS12C VS12A Pext VPGI Td2 Td1 1.25V 0.63V 1.25V OVP OVP/UVP/OCP/Pext OVP OVP/OCP 0.25V 3-Channel Secondary Monitoring IC Version:A.005 Page

4 未经授权而迳予重制、复制、使用或公开本文件,?为人得被追究侵权之相关民刑事责任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PS25A Pin Descriptions Pin No PIN NAME Descriptions