DESCRIPCIÓN

The LTM8054 is a 36VIN, buck-boost µModule(micromodule) regulator. Included in the package are the switching controller, power switches, inductor and support components. A resistor to set the switching frequency, a resistor divider to set the output voltage, and input and output capacitors are all that are needed to complete the design. Other features such as input and output average current regulation may be implemented with just a few components. The LTM8054 operates over an input voltage range of 5V to 36V, and can regulate output voltages between 1.2V and 36V. The SYNC input and CLKOUT output allow easy synchronization. The LTM8054 is housed in a compact overmolded ball grid array (BGA) package suitable for automated assembly by standard surface mount equipment. The LTM8054 is RoHS compliant.

 

CARACTERÍSTICAS

Fuente de alimentación conmutada Buck-Boost completa

Amplio rango de tensión de entrada: 5V a 36V

Amplio rango de tensión de salida: 1,2 V a 36 V

VIN May Be Greater than, Equal to or Less than VOUT

12V/1.8A Output from 6VIN

12V/3.4A Output from 12VIN

12V/5.4A Output from 24VIN

Up to 94% Efficient

Límites de corriente media de entrada y salida ajustables

Monitores de corriente de entrada y salida

Conectable en paralelo para aumentar la corriente de salida

Frecuencia de conmutación seleccionable: de 100 kHz a 800 kHz

Sincronización de 200 kHz a 700 kHz

11.25mm × 15mm × 3.42mm BGA Package

 

APLICACIONES

Dispositivos de alta potencia que funcionan con pilas

Control industrial

Regulador de tensión solar

Carga de baterías mediante energía solar

 

OPERACIÓN

The LTM8054 is a standalone nonisolated buck-boost switching DC/DC power supply. The buck-boost topology allows the LTM8054 to regulate its output voltage for input voltages both above and below the magnitude of the output, and the maximum output current depends upon the input voltage. Higher input voltages yield higher maximum output current. This converter provides a precisely regulated output voltage programmable via an external resistor divider from1.2V to 36V. The input voltage range is 5V to 36V, but the LTM8054 may be operated at lower input voltages if SVIN is powered by a voltage source above 5V. A simplified block diagram is given on the previous page. The LTM8054 contains a current mode controller, power switching elements, power inductor and a modest amount of input and output capacitance. The LTM8054 is a fixed frequency PWM regulator. The switching frequency is set by connecting the appropriate resistor value from the RT pin to GND. The output voltage of the LTM8054 is set by connecting the FB pin to a resistor divider between VOUT and GND. In addition to regulating its output voltage, the LTM8054 is equipped with average current control loops for both the input and output. Add a current sense resistor between IIN and VIN to limit the input current below some maximum value. The IINMON pin reflects the current flowing though the sense resistor between IIN and VIN. A current sense resistor between VOUT and IOUT allows the LTM8054 to accurately regulate its output current to a maximum value set by the value of the sense resistor. In general, the LTM8054 should be used with an output sense resistor to limit the maximum output current, as buck-boost regulators are capable of delivering large currents when the output voltage is lower than the input, if demanded.Furthermore, while the LTM8054 does not require an output sense resistor to operate, it uses information from the sense resistor to optimize its performance.If an output sense resistor is not used, the efficiency or output ripple may degrade, especially if the current through the integrated inductor is discontinuous. In some cases, an output sense resistor is required to adequately protect the LTM8054 against output overload or short-circuit. A voltage less than 1.2V applied to the CTL pin reduces the maximum output current. The current flowing through the sense resistor is reflected by the output voltage of the IOUTMON pin. Drive CTL to less than about 50mV to stop switching. Driving the SYNC pin will synchronize the LTM8054 to an external clock source. The CLKOUT pin sources a signal that is the same frequency but approximately 180° out of phase with the internal oscillator. If more output current is required than a single LTM8054 can provide, multiple devices may be operated in parallel. Refer to the Parallel Operation section of Applications Information for more details. An internal regulator provides power to the control circuitry and the gate driver to the power MOSFETs. This internal regulator draws power from the SVIN pin. The RUN pin is used to place the LTM8054 in shutdown, disconnecting the output and reducing the input current to less than 1µA. The LTM8054 is equipped with a thermal shutdown that inhibits power switching at high junction temperatures. The activation threshold of this function is above 125°C to avoid interfering with normal operation, so prolonged or repetitive operation under a condition in which the thermal shutdown activates may damage or impair the reliability of the device.