Renesas ISL6225EVAL2 User Manual

ISL6225EVAL2
Dual Switcher Evaluation Board Setup Procedure

General Description

This document describes the setup procedure for the
ISL6225 Evaluation Board dual switcher implementation.
The ISL6225 can control two output voltages adjustable from
0.9V to 5.5V. The ISL6225 combines two synchronous PWM
voltage regulators into a single IC. PWM1 and PWM2 output
voltages are set by a simple feedback voltage divider
connected across the outputs to GND. The feedback voltage
divider outputs are 0.9VDC, which are connected to the
VSEN1 and VSEN2 pins.
Automatic mode selection of constant-frequency synchronous
rectification at heavy load, and hysteretic diode-emulation at
light load, assure high efficiency over a wide range of
conditions. The hysteretic mode of operation can be disabled
separately on each PWM converter if constant-frequency
continuous-conduction operation is desired for all load levels.
Efficiency is further enhanced by using the lower MOSFET
R as the current sense element.
DS(ON)
Voltage-feed-forward ramp modulation, current mode control,
and internal feedback compensation provide fast response to
input voltage and output load transients.
In dual power supply applications the ISL6225 monitors the
output voltage of both CH1 and CH2. An independent
PGOOD (power good) signal is asserted for each channel
after its soft-start sequence has completed, and the output
voltage is within ±10% of the set point.
Built-in over-voltage protection prevents the output from
going above 115% of the set point by holding the lower
MOSFET on and the upper MOSFET off. When the output
voltage decays below the over-voltage threshold, normal
operation automatically resumes. Once the soft-start
sequence has completed, under-voltage protection will latch
the channel off if the output drops below 75% of its set point
value.
Adjustable over-current protection (OCP) monitors the
voltage drop across the R
DS(ON)
more precise current-sensing is required, an external current
sense resistor may be used.

Ordering Information

o
PART NUMBER TEMP. ( C)
ISL6225CA -10 to 85
ISL6225CA-T -10 to 85
AN1058 Rev 0.00
May 2003
of the lower MOSFET. If
PACKAGE PKG. DWG. #
28 Ld SSOP M28.15
28 Ld SSOP Tape M28.15
and Reel
USER'S MANUAL
Features
• Provides regulated output voltage in the range of 0.9V–5.5V
- High efficiency over wide load range
- Synchronous buck converter with hysteretic operation at
light load
- Inhibit Hysteretic mode on one, or both channels
• No current-sense resistor required
- Uses MOSFET R
DS(ON)
- Optional current-sense resistor for precision Over-
Current
• Over-Voltage, Under-Voltage and Over-Current protection
on both channels
• Under-voltage lock-out on VCC pin
• Dual input voltage mode operation
- Operates directly from battery 5V to 24V input
- Operates from 3.3V or 5V system rail
- VCC from 5V only
• Excellent dynamic response
- Combined voltage feed-forward and average current
mode control
• Power-good signal for each channel
• 300kHz switching frequency
- 180° channel to channel phase operation
Pinout
GND 1
LGATE1
2
PGND1 3
PHASE1
4
UGATE1 5
BOOT1
6
7
ISEN1 ISL6225
EN1
8
VOUT1
9
VSEN1 10
OCSET1 11
SOFT1
12
DDR 13
SSOP-28
VIN 14
What's Inside
This Evaluation Board Kit contains the following materials:
• ISL6225EVAL2 Evaluation Board
• ISL6225EVAL2 Board Evaluation Document
What is Needed
The following items will be needed to perform a complete
evaluation:
• 4 channel oscilloscope with probes
• 2 electronic loads
• 2 laboratory power supplies
• Precision digital multimeters
• Digital pulse generator
AN1058
Rev 0.00
May 2003
28 VCC
LGATE2
27
26 PGND2
PHASE2
25
UGATE2
24
BOOT2
23
22 ISEN2
21 EN2
VOUT2
20
VSEN2
19
18 OCSET2
SOFT2
17
16 PG2/REF
PG1
15
Page 1 of 11