19-0964; Rev 0; 8/07
MAX15005A Evaluation Kit
General Description
The MAX15005A evaluation kit (EV kit) is a fully assem-
bled and tested PCB that contains an 11W flyback DC-
DC converter for vacuum-fluorescent displays (VFDs) in
automotive applications. The circuit uses a MAX15005A
high-performance, current-mode pulse-width modulation
(PWM) controller in a 16-pin TSSOP package. The EV kit
circuit is configured for output voltages of 3V, 60V, and
110V, and provides up to 650mA, 12mA, and 55mA of
current from the respective output. Additionally, a 5V low-
dropout (LDO) voltage regulator output is provided that
can source up to 15mA. Power for the EV kit circuit is pro-
vided from a 6.5V to 16V DC source. The MAX15005A EV
kit input circuit can sustain a 40V transient.
High efficiency of up to 71% is achieved using a single-
transistor flyback DC-DC converter topology. Low cost
is achieved through the use of direct secondary-side
regulation that does not require optical couplers. Input
undervoltage lockout (UVLO), output overvoltage pro-
tection (OVP), and soft-start provide for a robust 11W
power supply.
Operation at 100kHz minimizes the size of the trans-
former and passive components.
Warning:
The MAX15005A EV kit is designed to operate
with high voltages. Dangerous voltages are present on
this EV kit and on equipment connected to it. Users who
power up this EV kit, or power the sources connected to
it, must be careful to follow safety procedures appropriate
to working with high-voltage electrical equipment.
Under severe fault or failure conditions, this EV kit may
dissipate large amounts of power, which could result in
the mechanical ejection of a component or of compo-
nent debris at high velocity. Operate this kit with care to
avoid possible personal injury.
♦
6.5V to 16V DC Input Range
♦
Outputs
3V Provides Up to 650mA (VFD Filament)
60V Provides Up to 12mA (VFD Grid)
110V Provides Up to 55mA (VFD Anode)
♦
Output Voltage Accuracy
110V (Anode) = ±3% (Regulated Output)
60V (Grid) = ±5% (Proportional Loading)
3V (Filament) = ±10% (Proportional Loading)
♦
71% Efficiency at 16V Input and Full Load
♦
5V LDO Output Provides Up to 15mA
♦
Hiccup Current-Limit and Overtemperature
Shutdown
♦
100kHz Switching Frequency
♦
Capacitor Adjustable Soft-Start
♦
High-Accuracy Undervoltage Lockout (UVLO)
♦
Output Overvoltage Protection (OVP)
♦
Capable of Synchronizing to an External Clock
♦
Low-Cost, Robust Flyback Design
♦
Fully Assembled and Tested
Features
Evaluates: MAX15005A
Ordering Information
PART
MAX15005AEVKIT+
TYPE
EV Kit
+Denotes
lead-free and RoHS-compliant.
Component List
DESIGNATION
C1
QTY
1
DESCRIPTION
330µF, 50V electrolytic capacitor
(12.5mm x 13.5mm)
Panasonic EEVFK1H331Q
0.1µF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H104K
1µF ±10%, 16V X7R ceramic
capacitors (0805)
Murata GRM21BR71C105K
DESIGNATION
C4
QTY
1
DESCRIPTION
100pF ±2%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H101G
1000pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H102J
4700pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GMR188R71H472K
C2
1
C5
1
C3, C10
2
C6
1
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX15005A Evaluation Kit
Evaluates: MAX15005A
Component List (continued)
DESIGNATION
C7
QTY
1
DESCRIPTION
47pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H470J
0.68µF ±10%, 16V X7R ceramic
capacitor (0805)
Murata GRM219R71C684K
560pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H561J
2200pF ±10%, 100V X7R ceramic
capacitor (0603)
Murata GRM188R72A222K
100pF ±10%, 63V C0G ceramic
capacitors (1206)
TKD C3216C0G2J101K
10µF, 200V electrolytic capacitor
(10mm x 10.5mm)
SANYO 200CE10FS
22µF, 80V electrolytic capacitor
(8mm x 10.2mm)
Panasonic EEEFK1K220P
330µF, 6.3V electrolytic capacitor
(8mm x 10.5mm)
SANYO 6CE330EX
2.2µF ±20%, 10V X5R ceramic
capacitor (0603)
AVX 0603ZD225MAT
4700pF ±10%, 100V X7R ceramic
capacitor (0805)
Murata GRM219R72A472K
100V, 1A super-fast diode (SMA)
Diodes Inc. ES1B-13-F
600V, 1A super-fast diode (SMB)
Diodes Inc. MURS160-F
400V, 1A super-fast diode (SMA)
Diodes Inc. MURS140-13-F
DESIGNATION
D4
QTY
1
DESCRIPTION
40V, 3A Schottky diode (SMA)
Diodes Inc. B340A-13-F
8.2V, 350mW ±5% Zener diode
(SOT23)
Central Semiconductor CMPZ5237B
2-pin headers
3-pin header
80V, 1.4A n-channel MOSFET (8-pin SO)
Vishay Si4896DY-T1-E3
11.5kΩ ±1% resistor (0603)
560Ω ±5% resistor (1210)
51Ω ±5% resistor (0805)
402kΩ ±1% resistor (0603)
1kΩ ±5% resistor (0603)
0.070Ω ±1% power resistor (2010)
IRC LRC-LR2010LF-01-R070-F
510Ω ±5% resistor (1206)
100kΩ ±5% resistor (1206)
220Ω ±5% resistor (1206)
36kΩ ±5% resistor (1206)
1.33MΩ ±1% resistor (0603)
12.1kΩ ±1% resistor (0603)
118kΩ ±1% resistor (0603)
1.33kΩ ±1% resistor (0603)
100Ω ±5% resistor (0805)
10Ω ±5% resistor (1210)
187kΩ ±1% resistor (0603)
47.5kΩ ±1% resistor (0603)
10kΩ ±5% resistor (0805)
232kΩ ±1% resistor (0603)
15µH, 10W, 1:3.438:2.813:0.188 turn,
100kHz transformer (10-pin gull wing)
Coiltronics CTX03-17677-R
MAX15005AAUE+ (16-pin TSSOP-EP)
Shunts (JU1, JU2, JU3)
PCB: MAX15005A Evaluation Kit+
D5
JU1, JU2
JU3
N1
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
R20
T1
U1
—
—
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
C8
1
C9
1
C11
1
C12, C14
2
C13
1
C15
1
C16
1
C17
1
C18
1
D1
D2
D3
1
1
1
2
_______________________________________________________________________________________
MAX15005A Evaluation Kit
Component Suppliers
SUPPLIER
AVX Corp.
Central Semiconductor
Cooper Electronic Tech./Coiltronics
Diodes Inc.
IRC
Murata Mfg. Co., Ltd.
Panasonic Corp.
SANYO Corp.
Vishay
PHONE
843-946-0238
631-435-1110
561-752-5000
805-446-4800
361-992-7900
770-436-1300
714-373-7366
619-661-6322
402-563-6866
WEBSITE
www.avxcorp.com
www.centralsemi.com
www.cooperet.com
www.diodes.com
www.irctt.com
www.murata.com
www.panasonic.com
www.sanyodevice.com
www.vishay.com
Evaluates: MAX15005A
Note:
Indicate that you are using the MAX15005A when contacting these component suppliers.
Quick Start
Required Equipment
Before beginning, the following equipment is needed:
•
•
One 6.5V to 16V power supply capable of providing
up to 3A
Three voltmeters
to less than 650mA, 12mA, and 55mA for each respec-
tive output detailed above in step 7.
Detailed Description
The MAX15005A EV kit is an 11W flyback DC-DC con-
verter that provides output voltages of 3V at up to
650mA, 60V at up to 12mA, and 110V at up to 55mA.
The MAX15005A flyback power supply is designed to
provide power to automotive VFDs. The circuit can be
powered from a 6.5V to 16V DC source, which provides
3A to the EV kit.
The flyback DC-DC converter achieves up to 71%
efficiency and the single-transistor topology provides
for a lower-cost design. The MAX15005A EV kit provides
cycle-by-cycle primary-side current-limit protection.
Current-sense resistor R6 senses the current through the
transformer’s (T1) primary winding, switching transistor
(N1), and turns off the transistor when the trip level of 0.3V
is reached. The MAX15005A EV kit features a resistor/
capacitor/diode (RCD) snubber network (R2, C11, and
D1) to minimize leakage energy ringing and clamp the
voltage at the drain of MOSFET N1 during switching.
Secondary-side regulation through feedback resistors
R13 and R14 provide ±3% regulation for the 110V
output (V_Anode). Resistors R8, R10, and R15 preload
the respective output and assist with overall regulation
at minimum loading. UVLO provides controlled turn-on
and shutdown during brownouts, power-up, or
power-down. The UVLO setting can be changed by
replacing resistor R18.
The MAX15005A analog soft-start allows the output volt-
age to slowly ramp up in a controlled manner within
56ms and is set by capacitor C8. The OVP is provided
by independently sensing the 110V output (V_Anode)
through resistors R11 and R12.
3
Procedure (Outputs)
The MAX15005A EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Connect a voltmeter to the FILAMENT+ and FILA-
MENT- pads.
2) Connect the second voltmeter to the V_GRID and
PGND pads.
3) Connect the third voltmeter to the V_ANODE and
PGND pads.
4) Verify that a shunt is installed across the pins of
jumpers JU1 (ON/OFF) and JU2 (SYNC).
5) Verify that a shunt is installed across pins 2-3 of
jumper JU3 (OVP).
6) Connect the power supply’s positive terminal to the
VIN pad. Connect the power supply’s ground to the
PGND pad.
7) Turn on the power supply above 7V and verify the
following voltmeters readings:
• FILAMENT = 3V
• V_GRID = 60V
• V_ANODE = 110V
The maximum current for each output should be limited
_______________________________________________________________________________________
MAX15005A Evaluation Kit
Evaluates: MAX15005A
The MAX15005A controller switches at a fixed 100kHz
frequency and is set by resistor/capacitor network R1
and C5. The switching duty cycle is varied to control
energy transfer to the outputs. The maximum duty cycle
is 50% for the EV kit’s discontinuous current-mode fly-
back design.
Table 2. Jumper JU2 SYNC Mode
Functions
SHUNT
POSITION
Installed
SYNC PIN
MAX15005A
OPERATING MODE
Internal clock mode
(100kHz set by R1
and C5)
Synchronization mode
(synchronized to an
external clock
frequency)
Shutdown Mode (Jumper- or Remote-
Control Method)
The MAX15005A EV kit features a jumper (JU1) that
can be used to shut down the flyback DC-DC convert-
er. An alternate shutdown method (remote control) can
be done with a user-supplied relay contact connected
to pin 2 of jumper JU1 of the EV kit. Table 1 shows
jumper options.
Connected to SGND
Connected to an
external TTL/CMOS
square-wave clock
source at the SYNC
and SGND pads
Not installed
Table 1. Jumper JU1 Shutdown Mode
SHUNT
POSITION
Installed
ON/OFF PIN
UVLO resistors R17
and R18 determine
startup voltage
Pulled low to PGND
through resistor R18
Relay contacts
connected between
JU1 pin 2
MAX15005A EV KIT
OUTPUT
MAX15005A enabled
Evaluating Other Current Limits, Input
UVLO, and Output OVP Shutdown
Current Limiting
The EV kit features current limiting for the transformer’s
primary current. The MAX15005A IC turns off switching
MOSFET N1 when the voltage at the MAX15005A CS
pin reaches 0.3V. Current-sense resistor R6 (0.07Ω)
limits the transformer peak primary current to 4.2A
(0.3V / 0.07Ω = 4.2A). To evaluate a lower current limit,
current-sense resistor R6 must be replaced with a
different surface-mount resistor (2010 size), as deter-
mined by the following equation:
R6 = (0.300V/I
PRIMARY
)
where I
PRIMARY
is the transformer’s maximum peak pri-
mary current.
Input UVLO (ON/OFF)
The MAX15005A EV kit features a brownout and input-
supply startup UVLO circuit that prevents operation
below the programmed input-supply-start voltage.
Resistors R17 and R18 set the input UVLO threshold of
the EV kit. To change the input UVLO voltage, replace
resistor R17 (or R18) with another surface-mount resis-
tor (0603 size). Using the desired startup voltage, resis-
tor R17 is then found by the following equation:
⎛
(
VIN
STARTUP
)
⎞
R17
= ⎜
−
1
⎟
x R18
1.230V
⎝
⎠
where VIN
STARTUP
is the desired startup voltage that
the EV kit starts at, and resistor R18 is typically in the
50kΩ range (47.5kΩ default). Refer to the
Startup
Operation/UVLO/ON/OFF
section of the MAX15005A
data sheet for additional information on the ON/OFF pin
of the MAX15005A IC.
Not installed
Shutdown mode
Not installed
Remote mode
SYNC Mode
The MAX15005A can be synchronized to an external
TTL/CMOS square-wave clock source. The 2-pin
jumper (JU2) selects the SYNC mode of operation or
100kHz internal frequency for the MAX15005A. Table 2
shows jumper options.
The TTL/CMOS square-wave clock source (from
105kHz to 130kHz) must provide the following signal
qualities:
• Output voltage:
Logic-low = 0 to 0.8V
Logic-high = 2V to 5.5V
•
•
•
Output frequency = 105kHz to 130kHz
Minimum positive-pulse width = 50ns
Connect the external square-wave clock to the
SYNC and PGND pads. Refer to the MAX15005A
data sheet for more information on the SYNC pin.
4
_______________________________________________________________________________________
MAX15005A Evaluation Kit
Output OVP Shutdown
The MAX15005A EV kit features an OVP circuit that pre-
vents operation above the programmed V_ANODE out-
put supply voltage (136V default). Jumper JU3 config-
ures the circuit for output OVP protection when the
shunt is placed across pins 2-3. Resistors R11 and R12
set the OVI threshold of the OVP circuit for the
MAX15005A IC. To evaluate other OVP voltages,
replace resistor R11 with another surface-mount resis-
tor (0603 size). Using the desired OVP voltage, resistor
R11 is then found by the following equation:
⎛
(
OVP
)
⎞
⎜
R11
= ⎜
−
1
⎟
x R12
⎟
1.228V
⎝
⎠
where OVP is the desired voltage that the circuit shut-
down is at and resistor R12 is typically in the 10kW
range (12.1kΩ default). See Table 3 for configuring
jumper JU3 for output OVP protection.
OVP circuit for the MAX15005A IC. To evaluate other
OVP voltages, replace resistor R20 with another sur-
face-mount resistor (0603 size). Using the desired OVP
voltage, resistor R20 is then found by the following
equation:
⎛
(
OVP
)
⎞
⎜
R20
= ⎜
−
1
⎟
x R12
⎟
1.228V
⎝
⎠
where OVP is the desired voltage that the circuit shut-
down is at and resistor R12 is typically in the 10kΩ
range (12.1kΩ default). See Table 3 for configuring
jumper JU3 for input OVP protection.
Evaluates: MAX15005A
Table 3. Jumper JU3 OVP Shutdown
SHUNT
POSITION
1-2
2-3*)
Not installed
OVI PIN
Sense VIN input
Sense V_ANODE
output
No sensing
OVP OPERATION
Input overvoltage
protection (load dump)
Output overvoltage
protection
OVP disabled
Input OVP Shutdown (Load Dump Protection)
The MAX15005A EV kit OVP circuit can be reconfigured
to provide load dump protection for VIN when it rises
above the programmed VIN supply voltage (24.7V
default). Jumper JU3 configures the circuit for input
OVP protection when the shunt is placed across pins 1-
2. Resistors R12 and R20 set the OVI threshold of the
*Default
position.
_______________________________________________________________________________________
5
京公网安备 11010802033920号
EEWORLD
