NOTE 4 BLUETOOTH BATTERY STATUS SOFTWARE
NOTE 4 BLUETOOTH BATTERY STATUS FREE

This capacity can be lower or higher than the nominal capacity depending on how your product uses the battery. For example, a capacity of 260mAh at 0.19mA.Įffective Capacity – This is the actual capacity of the battery in your product or application. Every manufacturer will specify the conditions under which this capacity is specified, and it typically includes temperature and current. Nominal Capacity – This is the capacity under nominal conditions. The actual capacity depends on the current being drawn and is better specified by Nominal and Effective parameters (unless the current draw is very low). A battery with 100mAh can theoretically provide a steady current of 100mA for one hour, or 50mAh for 2 hours, or 1mA current for 100 hours. Capacity is the amount of energy in a battery and is typically specified in mAh or Ah. Batteries, Lifetime and CurrentĮvery battery, regardless of the chemistry, has several common specifications that we’ll describe:Ĭapacity – Probably the most important parameter of any battery. This is typically 1.8V to 3.6V, but some devices can accept up to 5V which can be beneficial in some cases.

NOTE 4 BLUETOOTH BATTERY STATUS SOFTWARE

Creating a low power product requires optimization on the hardware, software and other layers.Īnother important factor to realize is that BLE devices need a certain voltage to operate. We’re not including any extra power required by sensors, other components or peripherals since they depend on the product, but they should be taken into account. Processing – the processor requires significant power while running the BLE stack as well as any other processing required.Amount of data sent – larger advertising packets require the BLE radio to stay on the air longer, drawing more current during this time.Many latest generation devices draw 3mA to 6mA peak, while older devices can draw 3x or more. Power output of the BLE device – the higher the output power the more current is required.Peak current consumption of BLE chipsets is affected by several factors: Central devices draw significantly more power, but since these are expected to be smartphones with large batteries, it’s not an issue. BLE was designed to be asymmetrical, with Peripheral devices designed to use as little power as possible. Note that we’re focusing here on BLE products that are running BLE in Peripheral mode. In these cases it’s possible to have a current draw of less than 200nA. It’s also possible to go to a deeper sleep mode where no RTC is running and the system in a low power mode, but this prevents a smartphone from connecting to a device. The average current of the system is then higher and depends on how often the system wakes up to send data. If the device wakes up periodically, then the current peaks for a few milliseconds during transmission and reception. When in sleep, the CPU is off, the BLE Radio isn’t transmitting, and most peripherals are stopped as well. This figure accounts for a running a Real Time Clock (RTC) which wakes the system periodically to advertise or send data. How much current they draw during sleep depends on the device, but a figure of around 1.5uA is typical of many SoCs. Most BLE products are designed to stay asleep as much as possible to conserve power, waking up to process and send data. Which part consumes more depends mainly on the application and duty cycle. Some BLE radios can reach a peak of 20mA when transmitting (or more if the output power increased). The Bluetooth radio is another part that can consume significant amounts of power. The processor can draw several mA when running. Power consumption in BLE SoCs is typically due to the processor and the BLE radio. Peripherals – I2C, SPI, UART, PWM, GPIO.BLE Radio – Complete radio and stack needed to connect to other BLE devices.Most modern BLE SoCs are very sophisticated devices that integrate almost everything needed to build a complete smart device: Their current consumption profile has a large effect on the product lifetime. Most BLE devices today are System on Chip (abbreviated SoCs). BLE Current Consumptionīefore we start talking about the batteries, we have to understand the BLE devices themselves and their power requirements.

NOTE 4 BLUETOOTH BATTERY STATUS FREE

As always, feel free to get in touch if you have questions. Every product and application is different, but with this information you can make better choices. This guide is designed to give you a broad overview of the choices in powering BLE products and the practical issues surrounding their use. Besides the popular Coin Cell batteries you will also see Alkaline, Lithium and many other chemistries. Since BLE was designed from the ground up for low power battery devices, it’s common to see a wide range of batteries used in designs.

Note 4 bluetooth battery status