ROCHESTER INSTITUTE OF TECHNOLOGY MICROELECTRONIC ENGINEERING Power Conditioning Electronics Dr. Lynn Fuller Webpage: http://people.rit.edu/lffeee 82 Lomb Memorial Drive Rochester, NY 14623-5604 Email: Lynn.Fuller@rit.edu Department webpage: http://www.rit.edu/microelectronic/ 5-10-20012 Power_Conditioning.ppt Page 1
OUTLINE Introduction Power Conditioning Voltage Regulators Analog Switches Two Phase Clocks Voltage Inverters, Doublers, Tripler's Boost Electronics Level Shifting Circuits Page 2
INTRODUCTION The design of microsystems involves the integration of MEMS, on chip custom integrated circuits, off chip electronics, such as power supply chips, microcontrollers and communication components. The integration is often done at the printed circuit board (PCB) level. This document will look at the power management electronics used in these systems. Page 3
Signal Conditioning Communication Multi-Sensor MEMs Chip MICROSYSTEM Power Management other. µp. Signal Conditioning Electronics Micro Controller Page 4
Unregulated 9 to 24 volts DC POWER CONDITIONING EXAMPLE LM317M Vout 1.2 to 37 500mA Positive Voltage Regulator +5 Volts mic2950 Vout 3.3 150mA Positive Voltage Regulator +3.3 Volts MAX1044 Vin 1.5 to 10 Vout = ~ -Vin -5 Volts UCC384 Vout -3.3 100mA -3.3 Volts Voltage Converter Negative Voltage Regulator Page 5
BASIC POSITIVE VOLTAGE REGULATOR Voltage Regulator BJT or MOS Transistor Pass Element Unregulated Power Supply + - Vx Vout R1 (e.g. transformer, rectifier, capacitor filter) - Av + Comparator + - Vref R2 Gnd R Load Vout = Vref(1+R1/R2) Page 6
POWER SUPPLY COMPONENTS Description Digikey Part Number Package ~Price POS Lin Regulator Variable LM317MBSTT3GOS SOT-223 $0.72 CT-ND POS Lin Regulator 3.3 Volt 576-1151-ND 8-SOIC $1.11 Voltage Converter CMOS SW-CAP MAX1044CPA+-ND 8-DIP $2.68 Voltage Converter CMOS SW-CAP MAX1044CSA+-ND 8-SOIC $3.26 NEG Lin Regulator 296-11417-5-ND 8-SOIC $5.60 8-DIP SOT-223 8-SOIC Page 7
VOLTAGE REGULATOR (Vref to Vout not to ground) Vin Positive Voltage Regulator LM317M Vout 1.2 to 37 500mA Vout = 1.25(1+R2/R1) R1 Vadj R2 Vout Gnd Note: see data sheets for LM317M-D.pdf the reference is between Vout and Vadj not between Vadj and ground. Page 8
VOLTAGE REGULATOR (Vref to Vout not to ground) Voltage Regulator BJT or MOS Transistor Pass Element Unregulated Power Supply (e.g. transformer, rectifier, capacitor filter) + - Vx Av - + Vref + - Vout R1 R2 Gnd R Load Vout = Vref(1+R2/R1) Page 9
MAX1044 VOLTAGE CONVERTER Page 10
SWITCHED CAPACITOR VOLTAGE CONVERTER MAX1044CSA+-ND CMOS 1.5 to10 Volt Supply Page 11
NEGATIVE VOLTAGE REGULATOR Vout = Vref(1+R1/R2) Page 12
SWITCHED CAPACITOR VOLTAGE TRIPLER 2 1 1 2 1 5 0 2 5 0 t C1 Vdd 1 1 C2 C Load R Load 2 When f1 is high switches put C1 and C2 in parallel with Vdd. When f2 is high switches put C1, C2 and Vdd in series, tripling the voltage to the load. Page 13
POWER CONDITIONING (BOOST CONVERTER) These circuits convert a low level DC (or AC) to high level DC voltage. Page 14
BOOST CONVERTER WITH ACTIVE RECTIFICATION Active rectification is a technique where diodes are replaced by transistor switches in rectification circuits. This can improve efficiency by elimination the 0.7 volt drop across the diode and reducing the series resistance. Electronic circuits turn on the transistor switch at the appropriate time thus the name synchronous or active rectification. Regulator Vin + - C Load Load Oscillator Step up converter with active rectification and output voltage regulation Page 15
POWER CONDITIONING ELECTRONICS Transformers can increase the voltage for ac signals. Voltage multiplier circuits exist for AC signals. DC signals can be switched on and off and thus create changing signals in inductors and transformers that can increase the voltage. These higher AC voltages can be rectified using diodes or switches and charge a battery or super capacitor. Transformers 1:10 to 1:100 Coilcraft Coilcraft Inductors 202uH to 390uH Page 16
LTC3105 SOLAR CELL TO SUPER CAPACITOR Page 17
LEVEL SHIFTING V(out) V(in) Page 18
LEVEL SHIFTING Page 19
REFERENCES 1. Dr. Fullers webpage http://people.rit.edu/lffeee Page 20
HOMEWORK POWER CONDITIONING 1. Sketch a schematic showing battery, switches and capacitors of the positive-to-negative switched capacitor voltage converter. 2. Design a 5 volt regulator using a 741 op amp and a BJT transistor. 3. Do a SPICE simulation. Page 21