Pololu TPS2116 Power Multiplexer Carrier with USB Type-C Connector

Модул за автоматично превключване между две DC захранвания с напрежение от 1,6 V до 5,5 V и с ток до 2,5А. Изграден е с Power Multiplexer Texas Instruments TPS2116 и е предназначен да осигурява непрекъснато захранване на устройства, подавано от два източника на захранване. Единият източник се свързва на VIN1 (или на USB-C порта), а вторият на VIN2, като модулът автоматично превключва на захранването с по-високото напрежение и блокира обратен ток към входовете. Важно: НЕ подавайте двете захранвания на USB-C порта и на VIN1, защото те са свързани в общ вход! Едното захранване трябва да се подаде към USB-C порта или към VIN1, а другото към VIN2! Важно: Модулът има вградени 4,7µF кондензатори на двата входа VIN1 и VIN2. При превключване на токове над няколкостотин mA или при по-дълги захранващи кабели, над 15cm, е препоръчително да се добави допълнителен електролитен кондензатор към всеки вход. Стойност от 33µF или повече. Допълнителният капацитет помага за намаляване на пикове в напрежението при превключване на захранванията. Такива пикове могат да надвишат максималното допустимо напрежение на чипа и да повредят модула. Освен в основния режим за автоматично превключване между по-високото от двете входни напрежение, модулът може да се настрой да работи и в priorite режим, където VIN1 може да бъде зададен като предпочитан вход чрез MODE и PR1 изводите. В този режим превключването към VIN2 не се определя от разликата между двете входни напрежения, а от нивото на PR1. Например, при MODE = HIGH и PR1 над 1V се избира VIN1, а при PR1 под 1V се избира VIN2. Нивото на напрежението на PR1 се задава чрез добавяне на резистор между VIN1 и PR1, чрез който се дефинира прага на превключване от VIN1 към VIN2 при спадане на VIN1 под определено ниво – допълнителна информация и формула за изчисление на резистора в секцията „Cоntrol input“ в подробното описание. Комплектът съдържа: Модул TPS2116 Power Multiplexer, USB priority – 1 бр. (няма конектори в комплекта) Характеристики: Power Multiplexer чип: Texas Instruments TPS2116 – datasheet Два входа за захранване: VIN1 и VIN2 USB Type-C VBUS е свързан към VIN1 Входно напрежение: 1,6V до 5,5V Максимален изходен ток: до 2,5A Автоматичен избор на входа с по-високо напрежение Блокира обратен ток към входните захранвания Изведени пинове MODE, PR1 и ST за допълнително управление на модула, като настройка на предпочитан вход, статус и др. – допълнителна информация в секцията Control inputs на подробното описание в страницата на продука. Изведени USB 2.0 сигнали D+ и D- Изведени CC1 и CC2 пинове от USB-C конектора Изводи с 2,54mm разстояние, подходящи за стандартни конектори Два монтажни отвора Размери платка: 25,4мм х 14мм Допълнителна информация: Pololu TPS2116 Power Multiplexer Carrier with USB Type-C Connector. Подробно описание TI TPS2116 datasheet Схема Размери Overview EN The Texas Instruments TPS2116 power multiplexer allows seamless switching between two power sources of 1.6 V to 5.5 V with up to 2.5 A of continuous current while blocking reverse current into either source. The power multiplexer (or mux) has an adjustable switching threshold that helps reduce output voltage droop when switching. Each input channel is controlled by an internal MOSFET switch, so the mux avoids the voltage drop that occurs when diodes are used to OR multiple power supplies together. Our TPS2116 carriers break out all of the chip’s features to 0.1″-spaced pins, making it easy to use with standard solderless breadboards. In addition, each board serves as a breakout for a USB Type-C connector that can be used to supply one of the input power rails. By default, the TPS2116 automatically selects the power source that has a higher voltage, but the board can be configured to prioritize VIN1 as the selected source until it falls below a configurable switching threshold. A common application of these multiplexers is enabling a device to be powered by USB or an external power supply, automatically choosing the appropriate source based on what is connected. We offer two versions of these TPS2116 boards that differ in how the USB 5 V supply (VBUS) is connected and whether it is preferred when the board is used in priority mode: Pinout Pin Description VIN1 Channel 1 power input. Can be connected to a 1.6 V to 5.5 V power source. Connected to VBUS (USB 5 V supply) on this version of the board. VIN2 Channel 2 power input. Can be connected to a 1.6 V to 5.5 V power source. VOUT Multiplexed power output. GND Common ground for power supplies, load, and USB. (All of the board’s GND pins are internally connected with each other and with GND from the USB connector.) MODE Mode control input. The board pulls this pin low, making the TPS2116 automatically select the higher of the two power sources by default. MODE can be tied high to enable priority or manual mode. See the Control inputs section below for more information. PR1 Switching control input. When MODE is high, VIN1 will be selected when PR1 is high and VIN2 will be selected when PR1 is low. The board pulls this pin low through a 15 kΩ resistor by default. See the Control inputs section below for more information. Driving PR1 high when MODE is low puts the TPS2116 into shutdown (the output is turned off). ST Open-drain status output that indicates which input is currently connected to the output. This pin is high impedance when VIN1 is selected and drives low otherwise (when VIN2 is selected or the mux is in shutdown mode). D− D+ USB 2.0 data signals broken out from USB connector. CC1 CC2 USB configuration channel signals broken out from USB connector. The board pulls both of these pins to GND through 5.11 kΩ termination resistors, making the USB-C port a power sink (device) and upstream-facing port (UFP) by default. Control inputs The MODE and PR1 pins can be used to override the default behavior of the TPS2116. The MODE pin determines the operating mode of the device. The board pulls this pin low by default, which results in autoswitching mode (sometimes called diode mode): the higher of the two input sources is automatically selected (connected to VOUT). However, when MODE is high, the selected input source is controlled by the PR1 pin instead: a voltage on PR1 above 1 V causes VIN1 to be selected (connected to VOUT), while a PR1 voltage below 1 V selects VIN2. You can drive the PR1 pin from an external source, such as an output pin from a microcontroller, to directly control the multiplexer’s switching (manual mode). Alternatively, the precise nature of the PR1 pin’s 1 V threshold makes it possible to use an external resistor to set a desired switching threshold for VIN1. By tying MODE to VIN1 (or otherwise driving it high) and connecting this external resistor between PR1 and VIN1, a voltage divider is created with the on-board 15 kΩ PR1 pull-down resistor, and the board will operate in priority mode, selecting VIN1 as long as the output of this voltage divider is greater than 1 V. (If PR1 drops below the 1 V threshold, the multiplexer switches to VIN2 regardless of whether VIN2 is lower or higher than VIN1.) The value of the added resistor determines the voltage at which the behavior of the multiplexer changes, as defined by the following equation: Vthreshold = ( (R / 15kΩ) + 1 ) х 1V For 5 V applications, adding a 47 kΩ resistor works well, since that sets the threshold to about 4.13 V. If PR1 is driven high while MODE is low, the TPS2116 turns off the output and enters a low-power shutdown state. Power connections without USB Power connections with USB The Type-C USB connector makes it easy to use USB as one of the two power sources. On this board (usb09a), the VBUS line from the USB connector is tied to VIN1. This allows you to power your circuit from either USB or an external power source connected to VIN2, with USB as the preferred power source if MODE and PR1 are high. Warning: It is important to be aware that while this board might appear to have three power inputs, two of those three are tied together (there are only two independent power inputs to the TPS2116). As such, you must take care to avoid creating a short circuit between USB power and an external power supply. For example, if you use this version with USB connected, any external power supply must be connected to VIN2; connecting it to VIN1 will create a short between this power supply and USB power. Other usage considerations This TPS2116 carrier board includes a 4.7μF capacitor on each of the two power inputs (VIN1 and VIN2). However, we strongly recommend adding additional capacitance to each input (an electrolytic capacitor of at least 33 μF is a good starting point) if you are switching more than a few hundred milliamps of current or if your power leads are longer than about 6 inches (150 mm). Otherwise, the rapid switching of current can cause LC voltage spikes that are much higher than the input voltage, and if these spikes exceed the maximum voltage rating of the TPS2116 (6 V), the chip can be destroyed. If the TPS2116 switches between power sources while the load is drawing substantial current, the new source’s voltage might drop with the applied load while the old source’s voltage rises as the load is removed. If this happens in priority mode with PR1 connected to a voltage divider on VIN1, the changing voltages could make PR1 cross the 1 V threshold again, and the multiplexer might start switching between the two inputs repeatedly (exacerbating the previously-mentioned LC spikes). To mitigate this behavior, you can add hysteresis to the switchover threshold by connecting an additional resistor between PR1 and ST. For example, with a divider on PR1 that includes a 47 kΩ pull-up and a 15 kΩ pull-down, adding a 1 MΩ resistor adds about 50 mV of hysteresis. This Microsoft Excel-based tool from TI can help calculate an appropriate hysteresis resistor for other scenarios (use the sheet named “TPS2116”). Finally, additional capacitance on VOUT can help reduce how much the output voltage drops while the TPS2116 switches. The board includes a 4.7μF capacitor on VOUT, but high-current applications might benefit from 100 μF or more of extra capacitance. Schematic diagram