Texas Instruments

The TPS40040 and TPS40041 dc-to-dc controllers are designed to operate from a 2.25-V to 5.5-V input source. To reduce the number of external components, several operating parameters are fixed internally; namely, frequency, soft start time, and short circuit protection (SCP) levels. For example, the operating frequencies of TPS40040/1 are 300 kHz/600 kHz, respectively. One of three short circuit threshold levels may be selected by the addition of an external resistor from the COMP pin to circuit ground. During power on, and before the internal soft start commands the output voltage to rise, the TPS40040/1 enters a calibration cycle, measures the current out of the COMP pin, and selects an internal SCP threshold voltage. At the end of the 1.6-ms calibration time, the output voltage is allowed to rise for a 4-ms soft start. During operation, the selected SCP threshold voltage is compared to the upper MOSFET’s voltage drop during its ON time to determine whether there is an overload condition. The packaging of the TPS40040/1 is unique in that the PowerPAD™ is used as an electrical ground connection as well as a thermal connection. The TPS40040 and TPS40041 dc-to-dc controllers are designed to operate from a 2.25-V to 5.5-V input source. To reduce the number of external components, several operating parameters are fixed internally; namely, frequency, soft start time, and short circuit protection (SCP) levels. For example, the operating frequencies of TPS40040/1 are 300 kHz/600 kHz, respectively. One of three short circuit threshold levels may be selected by the addition of an external resistor from the COMP pin to circuit ground. During power on, and before the internal soft start commands the output voltage to rise, the TPS40040/1 enters a calibration cycle, measures the current out of the COMP pin, and selects an internal SCP threshold voltage. At the end of the 1.6-ms calibration time, the output voltage is allowed to rise for a 4-ms soft start. During operation, the selected SCP threshold voltage is compared to the upper MOSFET’s voltage drop during its ON time to determine whether there is an overload condition. The packaging of the TPS40040/1 is unique in that the PowerPAD™ is used as an electrical ground connection as well as a thermal connection.

The TPS40042 DC/DC controller is designed to operate with an input source between a 3.0 V and 5.5 V. To reduce the number of external components, a number of operating parameters are fixed internally. The operating frequency for example, is internally set at 600 kHz. One of three short circuit threshold levels may be selected by the addition of an external resistor from the COMP pin to circuit ground (no resistor is the default setting). During power on, and before the internal soft start commands the output voltage to rise, the TPS40042 enters a calibration cycle, measures the current out of the COMP pin, and selects an internal SCP threshold voltage. At the end of the 1.5-ms calibration time, the output voltage is allowed to enter soft-start. During operation, the selected SCP threshold voltage is compared to the upper MOSFET’s voltage drop during its ON time to determine whether there is an overload condition. If the voltage across the MOSFET exceeds the threshold voltage, the TPS40042 counts seven continuous pulses before shutting completely OFF for seven soft start charge/discharge cycles, after which, the TPS40042 attempts to restart the output. During startup, both the high-side MOSFET switch and the synchronous rectifier are held in the OFF state until the internal soft start commands an output voltage higher than the voltage currently at the output. This may happen when the output is pre-biased at some voltage greater than zero and less than the desired regulation voltage. When the internal soft start first commands the output to rise, the pulse width of the synchronous rectifier is slowly increased from zero to the full 1-D conduction time by a number of discrete steps. In this way, inductor current is not allowed to reverse quickly, and ensures a monotonic startup of the output whether the output starts from zero or from a pre-bias level. If power is applied to the device while theEN(enable low) pin is allowed to float high, the TPS40042 remains OFF. Only when theENpin is pulled down towards ground is the controller allowed to start. The TPS40042 DC/DC controller is designed to operate with an input source between a 3.0 V and 5.5 V. To reduce the number of external components, a number of operating parameters are fixed internally. The operating frequency for example, is internally set at 600 kHz. One of three short circuit threshold levels may be selected by the addition of an external resistor from the COMP pin to circuit ground (no resistor is the default setting). During power on, and before the internal soft start commands the output voltage to rise, the TPS40042 enters a calibration cycle, measures the current out of the COMP pin, and selects an internal SCP threshold voltage. At the end of the 1.5-ms calibration time, the output voltage is allowed to enter soft-start. During operation, the selected SCP threshold voltage is compared to the upper MOSFET’s voltage drop during its ON time to determine whether there is an overload condition. If the voltage across the MOSFET exceeds the threshold voltage, the TPS40042 counts seven continuous pulses before shutting completely OFF for seven soft start charge/discharge cycles, after which, the TPS40042 attempts to restart the output. During startup, both the high-side MOSFET switch and the synchronous rectifier are held in the OFF state until the internal soft start commands an output voltage higher than the voltage currently at the output. This may happen when the output is pre-biased at some voltage greater than zero and less than the desired regulation voltage. When the internal soft start first commands the output to rise, the pulse width of the synchronous rectifier is slowly increased from zero to the full 1-D conduction time by a number of discrete steps. In this way, inductor current is not allowed to reverse quickly, and ensures a monotonic startup of the output whether the output starts from zero or from a pre-bias level. If power is applied to the device while theEN(enable low) pin is allowed to float high, the TPS40042 remains OFF. Only when theENpin is pulled down towards ground is the controller allowed to start.

The TPS4005x is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS4005x family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS4005x are also synchronizable to an external supply. They incorporate MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The TPS4005x uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range, and fast response to input line transients with near constant gain with input variation which eases loop compensation. The externally programmable current limit provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads. The TPS4005x is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS4005x family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS4005x are also synchronizable to an external supply. They incorporate MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The TPS4005x uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range, and fast response to input line transients with near constant gain with input variation which eases loop compensation. The externally programmable current limit provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads.

The TPS4005x is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS4005x family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS4005x are also synchronizable to an external supply. They incorporate MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The TPS4005x uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range, and fast response to input line transients with near constant gain with input variation which eases loop compensation. The externally programmable current limit provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads. The TPS4005x is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS4005x family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS4005x are also synchronizable to an external supply. They incorporate MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The TPS4005x uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range, and fast response to input line transients with near constant gain with input variation which eases loop compensation. The externally programmable current limit provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads.

The TPS40055 is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS40055 family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS40055 are also synchronizable to an external supply. The TPS40055 incorporates MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronousrectifier conduction. The TPS40055 uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range and fast response to input line transients with near constant gain with input variation which eases loop compensation. Theexternally programmable current limit provides pulse-by-pulse current limit, as well as a hiccup mode operation utilizing an internal fault counter for longer duration overloads. The TPS40055 is a family of high-voltage, wide input (8 V to 40 V), synchronous, step-down converters. The TPS40055 family offers design flexibility with a variety of user programmable functions, including soft-start, UVLO, operating frequency, voltage feed-forward, high-side current limit, and loop compensation. The TPS40055 are also synchronizable to an external supply. The TPS40055 incorporates MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronousrectifier conduction. The TPS40055 uses voltage feed-forward control techniques to provide good line regulation over the wide (4:1) input voltage range and fast response to input line transients with near constant gain with input variation which eases loop compensation. Theexternally programmable current limit provides pulse-by-pulse current limit, as well as a hiccup mode operation utilizing an internal fault counter for longer duration overloads.

The TPS40056 is part of a family of high-voltage, wide input, synchronous, step-down converters. The TPS40056 offers design flexibility with a variety of user programmable functions, including soft-start, operating frequency, high-side current limit, and loop compensation. The TPS40056 is also synchronizable to an external supply. It incorporates MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The externally programmable short circuit protection provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads. The TPS40056 is part of a family of high-voltage, wide input, synchronous, step-down converters. The TPS40056 offers design flexibility with a variety of user programmable functions, including soft-start, operating frequency, high-side current limit, and loop compensation. The TPS40056 is also synchronizable to an external supply. It incorporates MOSFET gate drivers for external N-channel high-side and synchronous rectifier (SR) MOSFETs. Gate drive logic incorporates anti-cross conduction circuitry to prevent simultaneous high-side and synchronous rectifier conduction. The externally programmable short circuit protection provides pulse-by-pulse current limit, as well as hiccup mode operation utilizing an internal fault counter for longer duration overloads.