Fluke 41B - Three-Phase Power Measurements

2-1
Chapter 2
Theory of Operation
Title Page
2-1. Introduction.......................................................................................... 2-3
2-2. Functional Block Description............................................................... 2-3
2-3. Circuit Operation.................................................................................. 2-5
2-4. Power-Up Sequence......................................................................... 2-5
2-5. Normal Operation ............................................................................ 2-6
2-6. Circuit Descriptions.............................................................................. 2-6
2-7. Power Supplies................................................................................. 2-6
2-8. Power-On Circuit......................................................................... 2-6
2-9. VCC............................................................................................. 2-6
2-10. -22 Volts ...................................................................................... 2-7
2-11. VEE.............................................................................................. 2-7
2-12. VDD............................................................................................. 2-7
2-13. VSS.............................................................................................. 2-7
2-14. VREF........................................................................................... 2-7
2-15. Low Battery Detection................................................................. 2-8
2-16. Power Reset................................................................................. 2-8
2-17. Input Conditioning........................................................................... 2-8
2-18. Difference Amplifier (Voltage Input).......................................... 2-8
2-19. Protection Circuit (Current Channel) .......................................... 2-8
2-20. Gain Amplifier............................................................................. 2-8
2-21. Latch (U1).................................................................................... 2-8
2-22. Anti-Alias Filter........................................................................... 2-9
2-23. Level Shifter ................................................................................ 2-9
2-24. A/D Converters................................................................................ 2-9
2-25. Digital Kernel................................................................................... 2-10
2-26. Digital Signal Processor (U2)...................................................... 2-10
2-27. Programmable Logic Device ....................................................... 2-10
2-34. SRAMs (U5,U6,U7).................................................................... 2-13
2-35. EPROM (U4)............................................................................... 2-13
2-36. EEPROM (U11)........................................................................... 2-13
2-37. Serial EEPROM (U22) ................................................................ 2-13
2-38. Keypad ............................................................................................. 2-13
2-39. Display............................................................................................. 2-13
2-40. LCD Module................................................................................ 2-13
2-41. BackLight .................................................................................... 2-14