Sharp LC-19LE510K (serv.man2) Service Manual ▷ View online
61
LC-19LE510
LC-22LE510
LC-24LE510
18. MP2012 (U176)
18.1.
General Description
The MP2012 is a fully integrated, internally compensated 1.2MHz fixed frequency PWM step-down
converter. It is ideal for powering portable equipment that runs from a single cell Lithium-Ion (Li+) Battery,
with an input range from 2.7V to 6V. The MP2012 can provide up to 1.5A of load current with output voltage
with an input range from 2.7V to 6V. The MP2012 can provide up to 1.5A of load current with output voltage
as low as 0.8V. It can also operate at 100% duty cycle for low dropout applications. With peak current mode
control and internal compensation, the MP2012 is stable with ceramic capacitors and small inductors. Fault
condition protection includes cycle-by-cycle current limiting and thermal shutdown.
condition protection includes cycle-by-cycle current limiting and thermal shutdown.
18.2.
Features
2.7-6V Input Operation Range
Output Adjustable from 0.8V to VIN
1μA Max Shutdown Current.
Up to 95% Efficiency
100% Duty Cycle for Low Dropout
Applications
1.2MHz Fixed Switching Frequency
Stable with Low ESR Output Ceramic
Capacitors
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Short Circuit Protection
Available in 6-pin 3x3mm QFN
18.3.
Pinning
Pin
#
Name
Description
1
FB
Feedback input. An external resistor divider from the output
to GND, tapped to the FB pin sets the output voltage.
to GND, tapped to the FB pin sets the output voltage.
2
GND, Exposed
Pad
Ground pin. Connect exposed pad to ground plane for
proper thermal performance.
3
SW
Switch node to the inductor.
4
PVIN
Input supply pin for power FET.
5
VIN
Input Supply pin for controller. Put small decoupling
ceramic near this pin.
6
EN
Enable input, “High” enables MP2012. EN is pulled to GND
with 1Meg internal resistor.
with 1Meg internal resistor.
17.
17.3
17.2
17.1
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LC-19LE510
LC-22LE510
LC-24LE510
19. RTA8283A (U23, U173)
19.1.
General Description
The RT8283A is a high-efficiency, monolithic synchronous step-down DC/DC converter that can deliver up
to 3A output current from a 4.5V to 23V input supply. The RT8283A's current mode architecture and
external compensation allow the transient response to be optimized over a wide range of loads and output
external compensation allow the transient response to be optimized over a wide range of loads and output
capacitors. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates
input current surge during start-up. The RT8283A also provides output under voltage protection and thermal
shutdown protection. The low current (<3μA) shutdown mode provides output disconnect, enabling easy
shutdown protection. The low current (<3μA) shutdown mode provides output disconnect, enabling easy
power management in battery powered systems. The RT8283A is available in a SOP-8 package.
19.2.
Features
±1.5% High Accuracy Feedback Voltage
Integrated N-MOSFET Switches
Current Mode Control
Fixed Frequency Operation : 340kHz
Output Adjustable from 0.8V to 20V
Up to 95% Efficiency
Thermal Shutdown Protection
18.
18.2
18.1
63
LC-19LE510
LC-22LE510
LC-24LE510
19.3.
Pinning
Pin No.
Pin
Name
Description
1
BOOT
Bootstrap for high-side gate driver. Connect a 0.1
μF or
greater ceramic capacitor from BOOT to SW pins.
2
VIN
Input Supply 4.5V to 23V. Must bypass with a suitably
large ceramic capacitor.
large ceramic capacitor.
3
SW
Phase Node--Connect to external L-C filter..
4, 9 (Exposed
Pad)
GND
Ground.
5
FB
Feedback Input pin is connected to the converter output.
It is used to set the output of the converter to regulate to
It is used to set the output of the converter to regulate to
the desired value via an internal res divider. For an
adjustable output, an external res divider is connected to
this pin.
6
COMP
Compensation Node. COMP is used to compensate the
regulation Control loop. Connect a series RC network
regulation Control loop. Connect a series RC network
from COMP to GND. In some cases, an additional
capacitor from COMP to GND is required.
7
EN
Enable Input Pin. Logic high enables the converter; a
logic low forces the RT8253A into shutdown mode.
Attach this pin to VIN with a 100kΩ pull up resistor for
automatic startup.
8
SS
Soft-Start Control Input. SS controls the soft-start period.
Connect a capacitor from SS to GND to set the soft-start
period. A 0.1
Connect a capacitor from SS to GND to set the soft-start
period. A 0.1
μF capacitor sets the soft-start period to
13.5ms.
18.3
64
LC-19LE510
LC-22LE510
LC-24LE510
20. MP1583 (U174)
20.1.
General Description
The MP1583 is a step-down regulator with a built-in internal Power MOSFET. It achieves 3A of continuous
output current over a wide input supply range with excellent load and line regulation. Current mode
operation provides fast transient response and eases loop stabilization. Fault condition protection
includes cycle-by-cycle current limiting and thermal shutdown. An adjustable soft-start reduces the
stress on the input source at start-up. The MP1583 requires a minimum number of external components,
providing a compact solution.
output current over a wide input supply range with excellent load and line regulation. Current mode
operation provides fast transient response and eases loop stabilization. Fault condition protection
includes cycle-by-cycle current limiting and thermal shutdown. An adjustable soft-start reduces the
stress on the input source at start-up. The MP1583 requires a minimum number of external components,
providing a compact solution.
20.2.
Features
3A Output Current
Programmable Soft-Start
100mΩ Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic Capacitors
Up to 95% Efficiency
20μA Shutdown Mode
Fixed 385KHz Frequency
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Wide 4.75V to 23V Operating Input Range
Output Adjustable from 1.22V to 21V
Under-Voltage Lockout
20.3.
Pinning
Pin
No.
Pin
Name
Description
1
BOOT
High-Side Gate Drive Bootstrap Input. BS supplies the drive for the
high-side N-Channel MOSFET switch.
high-side N-Channel MOSFET switch.
2
IN
Power Input. Drive IN with a 4.75V to 23V power source.
3
SW
Power Switching Out is the switching node that supplies power to the
output
4
GND
Ground.
5
FB
Feedback Input. FB senses the output voltage and regulates it. Drive
FB with a resistive voltage divider from the output voltage. FB
FB with a resistive voltage divider from the output voltage. FB
threshold is 1.222V.
6
COMP
Compensation Node is used to compensate the regulation control
loop.
loop.
7
EN
Enable/UVLO. A voltage greater than 2.71V enables operation. For
complete low current shutdown the EN pin voltage needs to be at less
complete low current shutdown the EN pin voltage needs to be at less
than 900mV. When the voltage on EN exceeds 1.2V, the internal
regulator will be enabled and the soft-start capacitor will begin to
charge. The MP1583 will start switching after the EN pin voltage
reaches 2.71V.
8
SS
Soft-Start Control Input. SS controls the soft-start period.
20. MP1583 (U174)
20.1.
General Description
The MP1583 is a step-down regulator with a built-in internal Power MOSFET. It achieves 3A of continuous
output current over a wide input supply range with excellent load and line regulation. Current mode
operation provides fast transient response and eases loop stabilization. Fault condition protection
includes cycle-by-cycle current limiting and thermal shutdown. An adjustable soft-start reduces the
stress on the input source at start-up. The MP1583 requires a minimum number of external components,
providing a compact solution.
output current over a wide input supply range with excellent load and line regulation. Current mode
operation provides fast transient response and eases loop stabilization. Fault condition protection
includes cycle-by-cycle current limiting and thermal shutdown. An adjustable soft-start reduces the
stress on the input source at start-up. The MP1583 requires a minimum number of external components,
providing a compact solution.
20.2.
Features
3A Output Current
Programmable Soft-Start
100mΩ Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic Capacitors
Up to 95% Efficiency
20μA Shutdown Mode
Fixed 385KHz Frequency
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Wide 4.75V to 23V Operating Input Range
Output Adjustable from 1.22V to 21V
Under-Voltage Lockout
20.3.
Pinning
Pin
No.
Pin
Name
Description
1
BOOT
High-Side Gate Drive Bootstrap Input. BS supplies the drive for the
high-side N-Channel MOSFET switch.
high-side N-Channel MOSFET switch.
2
IN
Power Input. Drive IN with a 4.75V to 23V power source.
3
SW
Power Switching Out is the switching node that supplies power to the
output
4
GND
Ground.
5
FB
Feedback Input. FB senses the output voltage and regulates it. Drive
FB with a resistive voltage divider from the output voltage. FB
FB with a resistive voltage divider from the output voltage. FB
19.
19.3
19.2
19.1
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