Texas Instruments TPS54560 Step-Down DC-DC Converter Evaluation Module TPS54560EVM-515 TPS54560EVM-515 데이터 시트
제품 코드
TPS54560EVM-515
SLVSBN0A – MARCH 2013 – REVISED MARCH 2014
8 Detailed Description
8.1 Overview
The TPS54560 is a 60 V, 5 A, step-down (buck) regulator with an integrated high side n-channel MOSFET. The
device implements constant frequency, current mode control which reduces output capacitance and simplifies
external frequency compensation. The wide switching frequency range of 100 kHz to 2500 kHz allows either
efficiency or size optimization when selecting the output filter components. The switching frequency is adjusted
using a resistor to ground connected to the RT/CLK terminal. The device has an internal phase-locked loop (PLL)
connected to the RT/CLK terminal that will synchronize the power switch turn on to a falling edge of an external
clock signal.
device implements constant frequency, current mode control which reduces output capacitance and simplifies
external frequency compensation. The wide switching frequency range of 100 kHz to 2500 kHz allows either
efficiency or size optimization when selecting the output filter components. The switching frequency is adjusted
using a resistor to ground connected to the RT/CLK terminal. The device has an internal phase-locked loop (PLL)
connected to the RT/CLK terminal that will synchronize the power switch turn on to a falling edge of an external
clock signal.
The TPS54560 has a default input start-up voltage of approximately 4.3 V. The EN terminal can be used to
adjust the input voltage undervoltage lockout (UVLO) threshold with two external resistors. An internal pull up
current source enables operation when the EN terminal is floating. The operating current is 146
adjust the input voltage undervoltage lockout (UVLO) threshold with two external resistors. An internal pull up
current source enables operation when the EN terminal is floating. The operating current is 146
μA under no load
condition (not switching). When the device is disabled, the supply current is 2
μA.
The integrated 92m
Ω high side MOSFET supports high efficiency power supply designs capable of delivering 5
amperes of continuous current to a load. The gate drive bias voltage for the integrated high side MOSFET is
supplied by a bootstrap capacitor connected from the BOOT to SW terminals. The TPS54560 reduces the
external component count by integrating the bootstrap recharge diode. The BOOT terminal capacitor voltage is
monitored by a UVLO circuit which turns off the high side MOSFET when the BOOT to SW voltage falls below a
preset threshold. An automatic BOOT capacitor recharge circuit allows the TPS54560 to operate at high duty
cycles approaching 100%. Therefore, the maximum output voltage is near the minimum input supply voltage of
the application. The minimum output voltage is the internal 0.8 V feedback reference.
supplied by a bootstrap capacitor connected from the BOOT to SW terminals. The TPS54560 reduces the
external component count by integrating the bootstrap recharge diode. The BOOT terminal capacitor voltage is
monitored by a UVLO circuit which turns off the high side MOSFET when the BOOT to SW voltage falls below a
preset threshold. An automatic BOOT capacitor recharge circuit allows the TPS54560 to operate at high duty
cycles approaching 100%. Therefore, the maximum output voltage is near the minimum input supply voltage of
the application. The minimum output voltage is the internal 0.8 V feedback reference.
Output overvoltage transients are minimized by an Overvoltage Transient Protection (OVP) comparator. When
the OVP comparator is activated, the high side MOSFET is turned off and remains off until the output voltage is
less than 106% of the desired output voltage.
the OVP comparator is activated, the high side MOSFET is turned off and remains off until the output voltage is
less than 106% of the desired output voltage.
The TPS54560 includes an internal soft-start circuit that slows the output rise time during start-up to reduce in-
rush current and output voltage overshoot. Output overload conditions reset the soft-start timer. When the
overload condition is removed, the soft-start circuit controls the recovery from the fault output level to the nominal
regulation voltage. A frequency foldback circuit reduces the switching frequency during start-up and overcurrent
fault conditions to help maintain control of the inductor current.
rush current and output voltage overshoot. Output overload conditions reset the soft-start timer. When the
overload condition is removed, the soft-start circuit controls the recovery from the fault output level to the nominal
regulation voltage. A frequency foldback circuit reduces the switching frequency during start-up and overcurrent
fault conditions to help maintain control of the inductor current.
10
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