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Power Electronics



◈ Power management integrated circuits (PMICs)


    ◇ Introduction

 

- Recently, most of electronic systems require that the power consumption is reduced and the reliability is enhanced.
Power management integrated circuits (PMICs) are a system block in a system-on-a-chip (SoC) device for managing power
consumption. PMICs are often used in liquid crystal display (LCD) applications using light-emitting diode (LED) backlight or
battery operated devices such as mobile phones and portable media players. PMICs include a DC-DC converter, an AC-DC
rectifier, a DC-AC invertor, and an AC-AC cycloconvertor. In mobile devices, the potable battery is used and DC-DC converters
are applied to generate required DC voltages. In many consumer electronics, a AC-DC rectifier is used to generate DC voltage
and the generated DC voltage is converted to required DC voltages by DC-DC converters. Many PMICs are often fabricated by
bipolar-CMOS-DMOS (BCD) process to sustain high voltage.

- Power management group in IELAB researches LED backlight driving system for notebooks and LCD TVs, PMIC for mobile
devices, battery management integrated circuit (BMIC) for mobile devices, AC-DC rectifier for LED lighting applications and
BCD process for PMIC.


 


    ◇ Research area
      · LED backlight driving system
          - LED backlight driving system for laptops
          - LED backlight driving system for LCD TVs

      · PMIC and BMIC for mobile devices
          - DC-DC converter
          - Low drop-out (LDO) regulator
          - Battery charger
          - Battery protection

      · AC-DC rectifier for LED lighting applications
          - AC-DC rectifier with LED control circuit
      · BCD device and process for PMIC
          - Lateral double diffused MOSFET (LDMOSFET) design
          - Modeling LDMOSFET
          - BCD process integration
          - Reliability

LCD television (TV) with LED backlight

Power management IC for mobile device

LED lighting for smart grid


    ◇ Research results
      · LED backlight driving system
          - LED backlight driving system for laptops

    ◇ Specifications
          - Process : 0.35-μm 5 V-60 V BCD process
          - Vin : 6 V ~ 27 V
          - Vout (max) : 60 V
          - ILED (max) : 30 mA
          - Number of channels : 6
          - Rising time of ILED : 86 ns
          - Resolution : 8-bit

Block diagram

Prototype

Measured results

Chip microphotograph


    ◇ Research results
      · LED backlight driving system
          - LED backlight driving system for LCD TVs

    ◇ Specifications
          - Process : 0.35-μm 5 V-60 V BCD process
          - Vin : 10 V ~ 36 V
          - Vout (max) : 60 V
          - ILED (max) : 30 mA
          - Number of channels : 48
          - Rising time of ILED : 4.8 ns
          - Resolution : 12-bit

          - Current uniformity < 2 %
 

Block diagram

Prototype

Measured results

Layout diagrams


    ◇ Research results
      · PMIC and BMIC for mobile devices
          - Single inductor multi-output (SIMO) DC-DC converter

    ◇ Specifications
          - Vin : 2.7 V ~ 4.2 V (Li-ion Battery)
          - Number of output : 5
          - Efficiency (max) : 88 %

Block diagram

Timing diagram

Simulated results


    ◇ Research results
      · PMIC and BMIC for mobile devices
          - Battery management system

    ◇ Specifications
          - Battery charger
          - Over voltage protection
          - Over current protection
          - Over temperature protection

Block diagram

Timing diagram

Layout diagram

Simulated results


    ◇ Research results
      · LED lighting
          - AC-DC rectifier with LED control circuit

    ◇ Specifications
          - Vin : 220 V / 110 V (AC 60 Hz)
          - P
output : 4 W ~ 20 W
          - Power efficiency (max) : 92 %
          - Power factor (min) : 97 %
          - Power line communication (PLC)

Block diagram

Board layout

Simulated results


    ◇ Research results
      · Device and process for PMIC
          - BCD process integration with 85 V LDMOSFET

    ◇ Specifications (85 V high voltage LDMOSFET)
          - Breakdown voltage : 120 V
          - R
on,sp of LDMOSFET : 1.5 mΩ·cm2
          - Second breakdown voltage : 92 V (@ V
gs = 12 V)

Cross section of BCD process

Measured results of 85 V LSD LDMOSFET


    ◇ Research results
      · Device and process for PMIC
          - 60 V LDMOSFET modeling

    ◇ Specifications
          - Peak accuracy < 10 %
          - RMS accuracy < 5 %

DC model of 60 V LDMOSFET

AC model of 60 V LDMOSFET

Measured results of DC characteristics

Measured results of AC characteristics


    ◇ Research results
      · Device and process for PMIC
          - Reliability (SOA)

    ◇ Specifications
          - Vout (max) : 100 V, Iout (max) : 10 A
          - SOA evaluation and UIS / CIS test

SOA test board

Measured results for SOA test

Measured results for UIS test


          - Reliability (ESD)

    ◇ Specifications

          - (LV / HV) input/output clamp and power clamp
          - HBM 3000 V & MM 300 V


Block diagram for ESD protection system

Measured results for HBM test