User's Manual

© SENSITECH INC. CONFIDENTIAL – CONTROLLED DOCUMENT Page 18 of 83
A Carrier Corp. Company
PART NUMBER T82002163
REV A
• Additional features include a high voltage bias regulator, automatic switch-over to external bias
for improved efficiency, thermal shutdown, frequency synchronization, cycle by cycle current
limit and adjustable line under-voltage lockout.
• The device is available in a power enhanced TSSOP-20 package featuring an exposed die attach
pad to aid thermal dissipation
• 7-42VDC input voltage and converts it to 6.25VDC/7A.
• This voltage output is for the Print Head.
6. LT1940, Dual Monolithic 1.4A, 1.1MHz Step-Down Switching Regulator
• The LT1940 is a dual current mode PWM step-down DC/DC converter with internal 2A power
switches.
• Both converters are synchronized to a single 1.1MHz oscillator and run with opposite phases,
reducing input ripple current.
• The output voltages are set with external resistor dividers, and each regulator has independent
shutdown and soft-start circuits.
• Each regulator generates a power-good signal when its output is in regulation, easing power
supply sequencing and interfacing with microcontrollers and DSPs.
• The LT1940’s 1.1MHz switching frequency allows the use of tiny inductors and capacitors,
resulting in a very small dual 1.4A output solution.
• Constant frequency and ceramic capacitors combine to produce low, predictable output ripple
voltage.
• With its wide input range of 3.6V to 25V
• Converts it to 3.3V/1.4A and 1.45V/1.4A. 1.45V is for VCORE which is the processor’s core
voltage.
• 3.3V is for the remaining voltages such as I/O and peripheral supply voltage.
7. LM2940, 1A Low Dropout Regulator
• The LM2940 positive voltage regulator features the ability to source 1A of output current with a
dropout voltage of typically 0.5V and a maximum of 1V over the entire temperature range.
• Furthermore, a quiescent current reduction circuit has been included which reduces the ground
current when the differential between the input voltage and the output voltage exceeds
approximately 3V.
• The quiescent current with 1A of output current and an input-output differential of 5V is therefore
only 30 mA.
• Higher quiescent currents only exist when the regulator is in the dropout mode (VIN − VOUT ≤
3V).
• The linear regulator (LDO) take a maximum of 26VDC input voltage and converts it to 5V/1A.
• This voltage output is for printer control board logic and boost converter.
8. LM2733, 0.6/1.6 MHz Boost Converters With 40V Internal FET Switch in SOT-23
• The LM2733 switching regulators are current-mode boost converters operating fixed frequency of
1.6 MHz (“X” option).
• The use of SOT-23 package, made possible by the minimal power loss of the internal 1A switch,
and use of small inductors and capacitors result in the industry's highest power density.
• Protection is provided through cycle-by-cycle current limiting and thermal shutdown.
• Internal compensation simplifies design and reduces component count.
• Boost Converter takes 3.3VDC from the Buck Converter and boosts the voltage output to
17.8VDC to 25.5VDC.