Step Down DC to DC Converter (Buck Controller) - TPS40195 and TPS5450 - Texas Instruments

Texas Instruments introduced TPS40195 and TPS5450 step down DC to DC converter (buck controller) that simplifies power management of design.

The TPS40195  - 4.5V to 20V Buck Controller with Synchronization and Power Good

TI's TPS40195 buck controller  provides features to enhance the power performance of a 4.5 V to 20 V supply system. The TPS40195 buck converter also can switch 180 degrees out of phase by cascading two chips. Combining with a master clock, the TPS40195 converter can also lowers EMI (electromagnetic interference).

The TPS40195  DC to DC converter implements voltage mode control with the switching frequency adjustable from 100 kHz to 600 kHz. Flexible features found on this device include selectable soft-start time, programmable short circuit limit, programmable undervoltage lockout (UVLO) and synchronization capability. An adaptive anti-cross conduction scheme is used to prevent shoot through current in the power FETs.

Texas Instruments TPS40195 Step Down DC to DC Converter (Buck Controller)

TPS40195  buck converter provides current detection at low duty cycles and limits energy into the system with an over-current sensing feature. The TPS40195 also supports control and protection features, such as shutdown control, power good output, adjustable under-voltage lockout, selectable digital soft start, programmable closed-loop soft start and short-circuit protection.

The TPS40195  buck converter also features short circuit detection, by comparing the voltage drop across the low-side MOSFET with a programmable threshold value set with a single external resistor. Pulse-by-pulse limiting is provided by sensing the voltage across the high-side MOSFET when it is on and terminating the cycle when the voltage drop rises above a fixed threshold of 550 mV. When the controller senses an output short circuit, both MOSFETs are turned off and a timeout period is observed before attempting to restart. This provides limited power dissipation in the event of a sustained fault.

Synchronization on TPS40195 is bi-directional. Devices can be synchronized 180° out of phase to a chosen master TPS40195 running at a fixed 250 kHz or 500 kHz, or can be synchronized to an outside clock source anywhere in the 100 kHz to 600 kHz range.

Power system designers can optimize the TPS40195 for efficiency by programming the switching frequency from 250 kHz to 600 kHz, or the controller can be synchronized via an external clock. By integrating the bootstrap diode, the device reduces system cost and saves board space.

Features of TPS40195  step-down DC to DC converter:

• Input Operating Voltage Range: 4.5 V to 20 V
• Output Voltage as Low as 0.591 V ± 0.5%
• 180° Bi-Directional Out-of-Phase Synchronization
• High and Low MOSFET Sense Overcurrent
• Internal 5-V Regulator
• 100 kHz to 600 kHz Switching Frequency
• Programmable UVLO and Hysteresis
• Enable and Power Good
• Selectable Soft-Start
• Thermal Shutdown at 150°C
• Pre-Bias Output Safe

Example of applications:

• Digital TV
• Networking Equipment
• Entry-Level and Midrange Servers
• Non-Isolated DC-DC modules

The TPS5450 - Wide Input Step Down SWIFT Converter

Along with the TPS40195, TI also introduced the TPS5450, a 5 Amperes Wide Input Step Down SWIFT Converter. This DC/DC converter integrates a low-resistance, high-side N-channel MOSFET, and provides tight voltage regulation accuracy under transient conditions. The TPS5450 supports a wide input voltage range of 5.5 V to 36 V and features a low shutdown quiescent current of 18 uA.

As a member of the SWIFT family of DC/DC regulators, the TPS5450 is a high-output-current PWM converter that integrates a low resistance high side N-channel MOSFET.  Using the ENA pin, shutdown supply current is reduced to 18 µA typically. Other features include an active-high enable, overcurrent limiting, overvoltage protection and thermal shutdown. To reduce design complexity and external component count, the TPS5450 feedback loop is internally compensated.

Features of TPS5450 Step Down SWIFT Converter:

• Wide Input Voltage Range: 5.5 V to 36 V
• High Efficiency Greater than 90%
• Up to 5-A Continuous (6-A Peak) Output Current
• Wide Output Voltage Range: Adjustable Down to 1.22 V with 1.5% Initial Accuracy
• Fixed 500 kHz Switching Frequency for Small Filter Size
• Internal Compensation Minimizes External Parts Count
• 18 µA Shut Down Supply Current
• Improved Line Regulation and Transient Response by Input Voltage Feed Forward
• System Protected by Overcurrent Limiting, Overvoltage Protection and Thermal Shutdown
• Available in Small Thermally Enhanced 8-Pin SOIC PowerPAD Package
• -40°C to 125°C Operating Junction Temperature Range

Example of Applications:

• LCD Displays, Plasma Displays
• High Density Point-of-Load Regulators
• 12-V/24-V Distributed Power Systems
• Battery Chargers

Price for  TPS40195 is $2.25 each (1K) and TPS5450 is $1.50 each (1K)

Further info:

• TPS40195 - The 4.5V to 20V Buck Controller with Synchronization and Power Good
• TPS5450 - The 5Ampere, Wide Input Step Down SWIFT Converter