Analog Front End IC for 4-7 cell Li-Ion/Li-Po Battery Pack



Ricoh Electronic Devices Co., Ltd. in Japan has launched a new advanced Analog Front End IC, a battery management IC for monitoring the condition of Lithium-Ion and Lithium-Polymer battery pack configurations consisting of 4 to 7-cells in series. Analog Front End ICs perform cell measurements processed by a host microcontroller resulting in a flexible concept shortening the lead time to the market. Applications include cordless power tools, electrical bicycles, robot vacuum cleaners, robot lawn mowers, drones and more.

The R5602 provides integral protectionby measuring the state of the individual cells and the battery pack in general. The microcontroller determines unsafe or faulty operating conditions such as overvoltage, undervoltage, overtemperature, overcurrent, cell imbalance, state of charge etcetera. The R5602 has an integrated charge pump for driving external high-side N-channel MOSFETs controlling the charge and discharge process.The use of high-side MOSFETs have a significant advantage to develop a circuit sharing the ground pin terminals of the AFE with other peripheral ICs in the circuit resulting in a better accuracy of cell measurements. All monitoring specifications are stored in software settings and can be easily updated if needed or a more sophisticated monitoring algorithm can be specified by design. A list of included advanced features:

·        High-accuracy cell voltage sampling (±30mV) (-20 to 85°C, VVCIN = 3 to 4.2V, Vdd ≥ 6.0 V. Cell voltages are balanced)

·        High-speed cell voltage sampling (<1 ms / measurement, including A/D conversion)

·        Current sense by external sense resistor, option to scale results by gain settings x2.5, x10, x20

·        Additional charge and discharge overcurrent and short circuit detection

·        Built-in 12-Bit A/D Converter

·        Embedded die temperature sensor as well as inputs for two additional temperature sensors

·        Allows random cell connection sequence during battery pack manufacturing (at CE pin = L)

·        Built-in passive cell balancing with internal switches and external resistors

·        Built-in cell open-wire detection switches

Multiple power modes are supported ranging from Max.1µA in standby mode up to Typ.150µA in normal operating condition. The IC switches automatically between idle and normal mode based on battery conditions but can be forced into the standby mode by controlling the CE pin to lower current consumption to a minimum.

An internal voltage regulator provides power to the host microcontroller IC, simplifying the circuit design and reducing board space. In order to select a suitable microcontroller of your preference, both I2C and SPI communication interface with or without CRC communication error detection are supported. An interrupt signal appears on the INTB output when a fault or not ready condition occurs. The R5602L is available in a 32 pins QFN0505-32C package, samples and evaluation boards are available from authorized local distribution channels and online partners Mouser and Digi-Key.

Features R5602:

Absolute Maximum Rating:                                                                                        -0.3 to 40 V

Power Consumption: Active mode / Standby mode:                          Typ. 150 µA / Max. 1.0 μA

Cell Measurement:                                                                          Built-in 12-bit A/D Converter

Cell Voltage Monitoring:                                                                         Input range: 1.5 to 4.5 V

Cell Voltage Monitoring Accuracy:(-20 to 85°C, VVCIN = 3 to 4.2V, Vdd ≥ 6.0 V. Cell voltages are balanced) ±30 mV

Digitization of Voltage across Sense Resistor:                                           Gain: x2.5 / x10 / x20

Temperature Monitoring:                                                                                    2 external NTCs

Die Temperature Monitoring and High Temperature alert

Voltage Regulator Output:                                                                                            Typ. 3.4V

Monitoring Speed:                                                                                           < 1 ms / 1 Monitor

Enhanced Overcurrent Protection:       Charge / Discharge overcurrent, Short-Circuit detection

Protection:                                                                        Built-in switch for Open-wire detection

                                                         Random cell connection sequence acceptable (CE = Low)

Charge / Discharge Control:                                                Dual High-side N-channel MOSFET

Built-in Cell Balancing:                                    Current control by external resistor (up to 20mA)

Communication Interface:                                           I2C and SPI Interface with / without CRC

Package R5602L:                                                                (5.0 x 5.0 x 0.8 mm) QFN0505-32C


For further information, please visit Ricoh's website