Texas Instruments

The TPS23758 device combines a Power over Ethernet (PoE) powered device (PD) interface, a 150-V switching power FET, and a current-mode DC-DC controller optimized for flyback topology. The high level of integration along with primary side regulation (PSR), spread spectrum frequency dithering (SSFD), and advanced startup makes the TPS23758 an ideal solution for size-constrained applications. The PoE implementation supports the IEEE 802.3at standard as a 13-W, Type 1 PD. The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for operation in continuous conduction mode (CCM) with secondary side synchronous rectification, resulting in optimum overall efficiency, regulation accuracy and step load response over multiple outputs (for example 5-V and 3.3-V output). Typically, the converter operates at a switching frequency of 250 kHz. SFFD and slew rate control helps to minimize the size and cost of the EMI filter. Advanced Startup allows the use of minimal bias capacitor while simplifying converter startup and hiccup design. Primary auxiliary power detect (APD) pin can be used to provide priority for a primary side power adapter. The DC-DC controller features adjustable soft-start, slope compensation, and blanking. For non-isolated applications, the buck topology is also supported by the TPS23758. The TPS23758 device combines a Power over Ethernet (PoE) powered device (PD) interface, a 150-V switching power FET, and a current-mode DC-DC controller optimized for flyback topology. The high level of integration along with primary side regulation (PSR), spread spectrum frequency dithering (SSFD), and advanced startup makes the TPS23758 an ideal solution for size-constrained applications. The PoE implementation supports the IEEE 802.3at standard as a 13-W, Type 1 PD. The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for operation in continuous conduction mode (CCM) with secondary side synchronous rectification, resulting in optimum overall efficiency, regulation accuracy and step load response over multiple outputs (for example 5-V and 3.3-V output). Typically, the converter operates at a switching frequency of 250 kHz. SFFD and slew rate control helps to minimize the size and cost of the EMI filter. Advanced Startup allows the use of minimal bias capacitor while simplifying converter startup and hiccup design. Primary auxiliary power detect (APD) pin can be used to provide priority for a primary side power adapter. The DC-DC controller features adjustable soft-start, slope compensation, and blanking. For non-isolated applications, the buck topology is also supported by the TPS23758.

These easy-to-use 8-pin integrated circuits contain all of the features needed to develop an IEEE 802.3af compliant powered device (PD). The TPS2375 family is a second generation PDC (PD Controller) featuring 100-V ratings and a true open-drain, power-good function. In addition to the basic functions of detection, classification and undervoltage lockout (UVLO), these controllers include an adjustable inrush limiting feature. The TPS2375 has 802.3af compliant UVLO limits, the TPS2377 haslegacyUVLO limits, and the TPS2376 has a programmable UVLO with a dedicated input pin. The TPS2375 family specifications incorporate a voltage offset of 1.5 V between its limits and the IEEE 802.3af specifications to accommodate the required input diode bridges used to make the PD polarity insensitive. Additional resources can be found on the TI Web site www.ti.com. These easy-to-use 8-pin integrated circuits contain all of the features needed to develop an IEEE 802.3af compliant powered device (PD). The TPS2375 family is a second generation PDC (PD Controller) featuring 100-V ratings and a true open-drain, power-good function. In addition to the basic functions of detection, classification and undervoltage lockout (UVLO), these controllers include an adjustable inrush limiting feature. The TPS2375 has 802.3af compliant UVLO limits, the TPS2377 haslegacyUVLO limits, and the TPS2376 has a programmable UVLO with a dedicated input pin. The TPS2375 family specifications incorporate a voltage offset of 1.5 V between its limits and the IEEE 802.3af specifications to accommodate the required input diode bridges used to make the PD polarity insensitive. Additional resources can be found on the TI Web site www.ti.com.

These easy-to-use 8-pin integrated circuits contain all of the features needed to develop an IEEE 802.3af-compliant powered device (PD). The TPS2375-1 and TPS2377-1 are second generation PDCs (PD Controllers) featuring a 100-V ratings and true open-drain, power-good function. These devices are auto-retry versions of selected TPS2375 family members. Information on the TPS2375/6/7 devices can be found on the TPS2375/6/7 data sheet (SLVS525A). In addition to the basic functions of detection, classification, and undervoltage lockout (UVLO), these controllers include an adjustable inrush limiting feature. The TPS2375-1 has 802.3af-compliant UVLO limits, and the TPS2377-1 has legacy UVLO limits. The TPS2375 family specifications incorporate a voltage offset of 1.5 V between its limits and the IEEE 802.3af specifications to accommodate the required input diode bridges used to make the PD polarity insensitive. Additional resources can be found on the TI Web site www.ti.com. These easy-to-use 8-pin integrated circuits contain all of the features needed to develop an IEEE 802.3af-compliant powered device (PD). The TPS2375-1 and TPS2377-1 are second generation PDCs (PD Controllers) featuring a 100-V ratings and true open-drain, power-good function. These devices are auto-retry versions of selected TPS2375 family members. Information on the TPS2375/6/7 devices can be found on the TPS2375/6/7 data sheet (SLVS525A). In addition to the basic functions of detection, classification, and undervoltage lockout (UVLO), these controllers include an adjustable inrush limiting feature. The TPS2375-1 has 802.3af-compliant UVLO limits, and the TPS2377-1 has legacy UVLO limits. The TPS2375 family specifications incorporate a voltage offset of 1.5 V between its limits and the IEEE 802.3af specifications to accommodate the required input diode bridges used to make the PD polarity insensitive. Additional resources can be found on the TI Web site www.ti.com.

The TPS23750 integrates the functionality of the TPS2375 with a primary side dc/dc PWM controller. The designer can create a front-end solution for PoE-PD applications with minimum external components. The TPS23770 is identical to the TPS23750 with the exception of the undervoltage lockout turn-on voltage, which is compatible with legacy systems. The PoE front end has all the necessary IEEE 802.3af functions including detection, classification, undervoltage lockout and inrush control. The PoE input switch is integrated within the TPS23750. The dc/dc controller section is designed to support flyback, forward, and nonsynchronous low-side switch buck topologies. The external switching MOSFET and current sense resistor provide flexibility in topology, power level, and current limit. The full-featured dc/dc controller includes programmable soft start, hiccup type fault limiting, 50% maximum duty cycle, programmable constant switching frequency, and a true voltage-output error amplifier. Additional protection features provide for robust designs. The TPS23750 integrates the functionality of the TPS2375 with a primary side dc/dc PWM controller. The designer can create a front-end solution for PoE-PD applications with minimum external components. The TPS23770 is identical to the TPS23750 with the exception of the undervoltage lockout turn-on voltage, which is compatible with legacy systems. The PoE front end has all the necessary IEEE 802.3af functions including detection, classification, undervoltage lockout and inrush control. The PoE input switch is integrated within the TPS23750. The dc/dc controller section is designed to support flyback, forward, and nonsynchronous low-side switch buck topologies. The external switching MOSFET and current sense resistor provide flexibility in topology, power level, and current limit. The full-featured dc/dc controller includes programmable soft start, hiccup type fault limiting, 50% maximum duty cycle, programmable constant switching frequency, and a true voltage-output error amplifier. Additional protection features provide for robust designs.

The TPS23785B is a combined Power over Ethernet (PoE) powered device (PD) interface and current-mode DC-to-DC controller optimized specifically for non-isolated converters. The PoE interface supports the IEEE 802.3at standard. The TPS23785B supports a number of input voltage ORing options including highest voltage, external adapter preference, and PoE preference. These features allow the designer to determine which power source will carry the load under all conditions. The PoE interface features the two-event, physical-layer classification necessary for compatibility with high-power midspan power sourcing equipment (PSE) per IEEE 802.3at. The detection signature pin can also be used to force power from the PoE source off. Classification can be programmed to any of the defined types with a single resistor. The DC-to-DC controller features two complementary gate drivers with programmable dead time. This simplifies design for highly-efficient flyback topologies utilizing secondary synchronous rectification. The second gate driver may be disabled if desired for single MOSFET topologies. The controller also features internal softstart, bootstrap startup source, current-mode compensation, and a 78% maximum duty cycle. A programmable and synchronizable oscillator allows design optimization for efficiency and eases use of the controller to upgrade existing power supply designs. Accurate programmable blanking, with a default period, simplifies the usual current-sense filter design trade-offs. The TPS23785B is a combined Power over Ethernet (PoE) powered device (PD) interface and current-mode DC-to-DC controller optimized specifically for non-isolated converters. The PoE interface supports the IEEE 802.3at standard. The TPS23785B supports a number of input voltage ORing options including highest voltage, external adapter preference, and PoE preference. These features allow the designer to determine which power source will carry the load under all conditions. The PoE interface features the two-event, physical-layer classification necessary for compatibility with high-power midspan power sourcing equipment (PSE) per IEEE 802.3at. The detection signature pin can also be used to force power from the PoE source off. Classification can be programmed to any of the defined types with a single resistor. The DC-to-DC controller features two complementary gate drivers with programmable dead time. This simplifies design for highly-efficient flyback topologies utilizing secondary synchronous rectification. The second gate driver may be disabled if desired for single MOSFET topologies. The controller also features internal softstart, bootstrap startup source, current-mode compensation, and a 78% maximum duty cycle. A programmable and synchronizable oscillator allows design optimization for efficiency and eases use of the controller to upgrade existing power supply designs. Accurate programmable blanking, with a default period, simplifies the usual current-sense filter design trade-offs.

The TPS2379 device is an 8-pin integrated circuit that contains all of the features needed to implement an IEEE802.3at type-2 powered device (PD) such as Detection, Classification, Type 2 Hardware Classification, and 140-mA inrush current limit during startup. The low 0.5-Ω internal switch resistance, combined with the enhanced thermal dissipation of the PowerPAD package, enables this controller to continuously handle up to 0.85 A. The TPS2379 integrates a low 0.5-Ω internal switch to allow for up to 0.85 A of continuous current through the PD during normal operation. The TPS2379 device supports higher-power applications through an external pass transistor. The TPS2379 contains several protection features such as thermal shutdown, current limit foldback, and a robust 100-V internal switch. The TPS2379 device is an 8-pin integrated circuit that contains all of the features needed to implement an IEEE802.3at type-2 powered device (PD) such as Detection, Classification, Type 2 Hardware Classification, and 140-mA inrush current limit during startup. The low 0.5-Ω internal switch resistance, combined with the enhanced thermal dissipation of the PowerPAD package, enables this controller to continuously handle up to 0.85 A. The TPS2379 integrates a low 0.5-Ω internal switch to allow for up to 0.85 A of continuous current through the PD during normal operation. The TPS2379 device supports higher-power applications through an external pass transistor. The TPS2379 contains several protection features such as thermal shutdown, current limit foldback, and a robust 100-V internal switch.