MAX15005AAUE+T Maxim Integrated Products, MAX15005AAUE+T Datasheet - Page 11

• Manufacturer Part Number: MAX15005AAUE+T
• Description: IC PWR SUPPLY CNTRLR 16-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX15005AAUE+T

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 1MHz
• Duty Cycle: 81.5%
• Voltage - Supply: 4.5 V ~ 40 V
• Buck: No
• Boost: Yes
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: Yes
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Frequency-max: 1MHz
• Duty Cycle (max): 80 %
• Output Voltage: 1.23 V to 100 V
• Output Current: 1000 mA
• Mounting Style: SMD/SMT
• Switching Frequency: 15 KHz to 500 KHz
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Synchronous Pin: Yes
• Topology: Boost, Flyback, Forward
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX15004A/B/MAX15005A/B are high-perfor-
mance, current-mode PWM controllers for wide input-
voltage range isolated/nonisolated power supplies.
These controllers are for use as general-purpose boost,
flyback, and SEPIC controllers. The input voltage range
of 4.5V to 40V makes it ideal in automotive applications
such as vacuum fluorescent display (VFD) power sup-
plies. The internal low-dropout regulator (V
tor) enables the MAX15004A/B/MAX15005A/B to
operate directly from an automotive battery input. The
input operating range can be as low as 2.5V when an
external source (e.g. bootstrap winding output) is
applied at the V
range allows device operation from cold crank to auto-
motive load dump.
The undervoltage lockout (ON/OFF) allows the devices
to program the input-supply startup voltage and ensures
predictable operation during brownout conditions.
The devices contain two internal regulators, V
REG5. The V
and REG5 regulator output voltage at 5V ±2%. The
V
sinking up to 30mA current. The input undervoltage
lockout (UVLO) circuit monitors the V
turns off the converter when the V
below 3.5V (typ). See the Internal Regulators V
REG5 section for a method to obtain lower than 4.5V
input operation with the MAX15004/MAX15005.
An external resistor and capacitor network programs
the switching frequency from 15kHz to 500kHz. The
MAX15004A/B/MAX15005A/B provide a SYNC input for
synchronization to an external clock. The OUT (FET-dri-
ver output) duty cycle for the MAX15004A/B is 50%.
The maximum duty cycle can be set on MAX15005A/B
by selecting the right combination of RT and CT. The
RTCT discharge current is trimmed to 2%, allowing
accurate setting of the duty cycle for the MAX15005.
An internal slope-compensation circuit stabilizes the
current loop when operating at higher duty cycles and
can be programmed externally.
The MAX15004/MAX15005 include an internal error
amplifier with 1% accurate reference to regulate the
output in nonisolated topologies using a resistive
divider. The internal reference connected to the nonin-
verting input of the error amplifier can be increased in a
controlled manner to obtain soft-start. A capacitor con-
nected at SS to ground programs soft-start to reduce
inrush current and prevent output overshoot.
The MAX15004/MAX15005 include protection features
like hiccup current limit, output overvoltage, and thermal
CC
Flyback/Boost/SEPIC Power-Supply Controllers
output includes a 10.4V clamp that is capable of
CC
CC
regulator output voltage is set at 7.4V
______________________________________________________________________________________
input. The 2.5V to 40V input voltage
Detailed Description
CC
CC
voltage drops
voltage and
4.5V to 40V Input Automotive
CC
CC
CC
regula-
and
and
shutdown. The hiccup current-limit circuit reduces the
power delivered to the electronics powered by the
MAX15004/MAX15005 converter during severe fault con-
ditions. The overvoltage circuit senses the output using
the path different from the feedback path to provide
meaningful overvoltage protection. During continuous
high input operation, the power dissipation into the
MAX15004/MAX15005 could exceed its limit. Internal
thermal shutdown protection safely turns off the converter
when the junction heats up to 160°C.
The advantages of current-mode control overvoltage-
mode control are twofold. First, there is the feed-for-
ward characteristic brought on by the controller’s ability
to adjust for variations in the input voltage on a cycle-
by-cycle basis. Secondly, the stability requirements of
the current-mode controller are reduced to that of a sin-
gle-pole system unlike the double pole in voltage-mode
control.
The MAX15004/MAX15005 offer peak current-mode
control operation to make the power supply easy to
design with. The inherent feed-forward characteristic is
useful especially in an automotive application where the
input voltage changes fast during cold-crank and load
dump conditions. While the current-mode architecture
offers many advantages, there are some shortcomings.
For higher duty-cycle and continuous conduction mode
operation where the transformer does not discharge
during the off duty cycle, subharmonic oscillations
appear. The MAX15004/MAX15005 offer programmable
slope compensation using a single capacitor. Another
issue is noise due to turn-on of the primary switch that
may cause the premature end of the on cycle. The cur-
rent-limit and PWM comparator inputs have leading-
edge blanking. All the shortcomings of the
current-mode control are addressed in the MAX15004/
MAX15005, making it ideal to design for automotive
power conversion applications.
The internal LDO converts the automotive battery volt-
age input to a 7.4V output voltage (V
put is set at 7.4V and operates in a dropout mode at
input voltages below 7.5V. The internal LDO is capable
of delivering 20mA current, enough to provide power to
internal control circuitry and the gate drive. The regulat-
ed V
absolute maximum gate voltage rating of the MOSFET
especially during the double battery and load dump
conditions. An auxiliary winding output can be fed to
the V
The bootstrap winding is not necessary for proper
CC
CC
keeps the driver output voltage well below the
output once the power supply is turned on.
Internal Regulators V
Current-Mode Control Loop
CC
CC
). The V
and REG5
CC
out-
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