MIC2111B Eval Board User Guide

High-Performance, Multi-Mode,
Step-Down Controller
MIC2111B Evaluation Board
General Description
The MIC2111B is a programmable-frequency, valleycurrent/voltage-mode PWM controller that provides the
control and protection features necessary for power
devices and drivers that use current-sensing across the
inductor. The MIC2111B provides a single tri-state PWM
logic signal to DrMOS modules to realize low output
voltage, high current power supply. The device has
precision enable and power good (PG) functions for the
sequencing of multiple power supplies. In addition, the
solution is compatible with intelligent power stages in a
high-current, step-down DC/DC converter.
The MIC2111B evaluation board operates over an input
supply range of 5.5V to 16V and provides a regulated
output at up to 20A of load current. The output voltage is
adjustable down to 0.6V with a typical accuracy of ±1%.
The evaluation board operates at a switching frequency of
500kHz, in valley current mode.
The MIC2111B utilizes a programmable control
architecture. The MIC2111B evaluation board is
configured for valley current mode control. An
undervoltage lockout feature is provided to ensure proper
operation under power sag conditions. An adjustable softstart feature is provided to reduce inrush current. An
adjustable current-limit is provided. “Hiccup” mode shortcircuit protection and thermal shutdown ensures protection
of the IC during fault conditions.
The basic parameters of the evaluation board are:
•
VIN supply: 5.5V to 16V
•
Output: 1.2V at 20A
•
500kHz switching frequency (Adjustable from
200kHz to 2MHz)
•
Control mode: Valley current mode (Adjustable to
voltage mode)
The customer can configure the MIC2111B evaluation
board to operate in voltage mode through the following
jumper selections.
Control Mode
P1
P2
Valley Current
Mode
Pins 1-2
Pins 1-2
Voltage Mode
Pins 2-3
OPEN
For information about compensation component selection,
see the MIC2111 datasheet on Micrel’s website at:
www.micrel.com.
Requirements
The MIC2111B evaluation board requires only a single
power supply with at least 10A current capability. The
MIC2111B has an on-board 5V LDO to power the internal
biasing of the MIC2111B IC and DrMOS gate drive supply.
Power-up Precautions
The evaluation board does not have reverse polarity
protection. Applying a negative voltage to the VIN terminal
may damage the device. In addition, the maximum VIN
operating voltage of the MIC2111B evaluation board is
16V.
Ordering Information
Part Number
Description
MIC2111BYMT
MIC2111B Evaluation Board
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 14, 2015
Revision 1.1
Micrel, Inc.
MIC2111B Evaluation Board
Oscillator Frequency
The MIC2111 has an internal oscillator by which the
frequency can be set through an external resistor at the
FREQ pin. The switching frequency can be programmed
from 200kHz to 2MHz by using the following equation.
Getting Started
1. Connect a supply to the VIN and GND terminals.
Pay careful attention to the polarity and the supply
range (5.5V < VIN < 16V). An ammeter may be placed
between the input supply and the VIN terminal to the
evaluation board. Ensure that the supply voltage is
monitored at the VIN terminal. The ammeter and/or
power lead resistance can reduce the voltage supplied
to the input. Do not apply power until Step 4.
RFREQ =
2. Connect the load to the VOUT and ground
terminals.
The load can be either passive (resistive) or active (as
in an electronic load). An ammeter can be placed
between the load and the VOUT terminal. Ensure that
the output voltage is monitored at the VOUT terminal.
Soft-Start/Soft-Stop (SS)
The MIC2111 has digital soft-start/soft-stop (SS) to avoid
high inrush current in the input supply lines. The soft-start
time can be programmed with an external resistor
connected from the SS pin to GND. Table 1 illustrates
resistor values and soft-start times. Soft-stop time is the
same as the programmed soft-start time (contact the
factory for instructions on disabling soft-stop).
Table 1. Soft-Start Programming
4. Turn on the power.
Turn on the VIN power supply and verify that the
output voltage is regulated to 1.2V.
Evaluation Board Description
Output Voltage
The output voltage on the MIC2111B evaluation board is
adjustable. It is set by adjusting the feedback resistors and
using the following equation.
𝑽𝑽𝑽𝑽𝑽𝑽𝑽𝑽 = 𝑽𝑽𝑭𝑭𝑭𝑭 𝒙𝒙 �𝟏𝟏 +
𝑹𝑹𝑹𝑹𝑹𝑹
�
Eq. 1
where VFB = 0.6V and R11 is 4.99kΩ for a 1.2V output
voltage. Leaving R11 open gives a 0.6V output voltage.
The output can be adjusted from 0.6V to 3.46V by
changing the value of R11 according to the equation
above.
The output voltage should not be set in excess of 3.46V
due to the need for headroom for the current sense
amplifier of MIC2111B. Please refer to the Application
Information section of the MIC2111 datasheet for setting
the output voltage.
October 14, 2015
Eq. 2
where FSW = the desired switching frequency in Hz.
3. Enable input.
An EN connector is provided on the evaluation board
for users to easily access the enable feature. The
output of the MIC2111B turns on when VCC exceeds
the UVLO threshold. The output of the MIC2111B
evaluation board may be turned off by shorting the EN
pin to ground.
𝑹𝑹𝑹𝑹𝑹𝑹
𝟏𝟏𝟏𝟏𝟏𝟏𝟏𝟏
𝑭𝑭𝑺𝑺𝑺𝑺[Ω]
2
E96 Range Resistance
Soft-Start
6.19kΩ
64µs
19.1kΩ
128µs
30.9kΩ
256µs
44.2kΩ
512µs
56.2kΩ
768µs
68.1kΩ
1024µs
80.6kΩ
1536µs
93.1kΩ
2048µs
105kΩ
3072µs
118kΩ
4096µs
130kΩ
6144µs
143kΩ
8192µs
154kΩ
16384µs
169kΩ
24576µs
182kΩ
32768µs
Open
2048µs
Revision 1.1
Micrel, Inc.
MIC2111B Evaluation Board
Evaluation Board Performance
October 14, 2015
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Micrel, Inc.
MIC2111B Evaluation Board
Evaluation Board Schematic
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Micrel, Inc.
MIC2111B Evaluation Board
Bill of Materials
Item
Part Number
C1
C1608X7R1C684K080AC
C2, C21, C24,
C30
C1608C0G1H100D
C3, C7, C16, C17,
C23,C31, R2, R6,
R13, R15, R16,
R17, R22, R26
OPEN
C4, C9, C18, C19,
C27,C32,C33,C34
Manufacturer
(1)
Qty.
0.68µF Ceramic Capacitor, X7R, 0603 Size, 16V
1
TDK
10pF Ceramic Capacitor, COG, 0603 Size, 50V
4
C1608X5R1E105K
TDK
1µF Ceramic Capacitor, X5R, 0603 Size, 25V
6
C5
C1608C0G1H820J
TDK
82pF Ceramic Capacitor, COG, 0603 Size, 50V
1
C6, C22
C1608C0G1H102J
TDK
1nF Ceramic Capacitor, COG, 0603 Size, 50V
2
C8, C10
C3225X5R0J226M/1.60
TDK
22µF Ceramic Capacitor, X5R, 1210 Size, 6.3V
2
C11, C13
C3225X5R0J107M
TDK
100µF Ceramic Capacitor, X5R, 1210 Size, 6.3V
2
C12, C20
C1608X7R1E104K
100nF Ceramic Capacitor, X7R, 0603 Size, 25V
2
C15
6SVP470MX
470µF OS-CON Capacitor, 6.3V
1
C25, C28, C29
C3225X5R1E106M
10µF Ceramic Capacitor, X5R, 1210 Size, 25V
2
C26
EEEFP1E471AP
470µF Alluminium Capacitor, 25V
1
0.4µH inductor, 37A saturation current
1
10Ω Resistor,0603 Size, 1%
4
L1
744325040
TDK
Description
TDK
Panasonic
(2)
TDK
Panasonic
(3)
Wurth Electric
Vishay Dale
(4)
R1, R2, R3, R10
CRCW060310R0FKEA
R4, R5, R7, R9,
R29, R30
CRCW060310K0FKEA
Vishay Dale
10kΩ Resistor,0603 Size, 1%
4
R8
CRCW0603866RFKEA
Vishay Dale
866Ω Resistor,0603 Size, 1%
1
R11, R14
CRCW06034K99FKEA
Vishay Dale
4.99kΩ Resistor,0603 Size, 1%
2
R11, R14
CRCW06034K99FKEA
Vishay Dale
4.99kΩ Resistor,0603 Size, 1%
2
R12, R31, RSW
CRCW06030000Z0EA
Vishay Dale
0Ω Resistor,0603 Size, 1%
3
R18, R23
CRCW06031R21FKEA
Vishay Dale
1.21Ω Resistor,0603 Size, 1%
2
R19
CRCW060311K0FKEA
Vishay Dale
11kΩ Resistor,0603 Size, 1%
1
R20
CRCW06031K00FKEA
Vishay Dale
1kΩ Resistor,0603 Size, 1%
1
R21
CRCW0603147KFKEA
Vishay Dale
147kΩ Resistor,0603 Size, 1%
1
R24
CRCW06035K49FKEA
Vishay Dale
5.5kΩ Resistor,0603 Size, 1%
1
R25
CRCW0603200KFKEA
Vishay Dale
200kΩ Resistor,0603 Size, 1%
1
R27
CRCW0603118KFKEA
Vishay Dale
118kΩ Resistor,0603 Size, 1%
1
R28
CRCW0603188KFKEA
Vishay Dale
188kΩ Resistor,0603 Size, 1%
1
U1
MIC2111B
High-Performance, Multi-Mode, Step-Down
Controller
1
U2
SiC780ACD
Integrated DrMOS power stage
1
U3
MIC5209-5.0YS
500mA Low Noise LDO Regulator
1
(5)
Micrel, Inc.
Vishay
Micrel, Inc.
Notes:
1. TDK: www.tdk.com.
2. Panasonic: www.industrial.panasonic.com.
3. Wurth Electronic: www.we-online.com.
4. Vishay Dale: www.vishay.com.
5. Micrel, Inc.: www.micrel.com.
October 14, 2015
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Revision 1.1
Micrel, Inc.
MIC2111B Evaluation Board
PCB Layout Recommendations
Top Layer
Mid Layer 1
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Revision 1.1
Micrel, Inc.
MIC2111B Evaluation Board
PCB Layout Recommendations (Continued)
Mid Layer 2
Bottom Layer
October 14, 2015
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Revision 1.1
Micrel, Inc.
MIC2111B Evaluation Board
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high-performance linear and power, LAN, and timing & communications
markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock
management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company
customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products.
Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and
advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network
of distributors and reps worldwide.
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical
implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2015 Micrel, Incorporated.
October 14, 2015
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