Electrification of automobile by our power management ICs
Functional Safety
Implementation of Safety Mechanisms
Functional Safety
Functional safety is generally defined as "to ensure safety at an acceptable level by introducing functions to ensure safety against harm." In other words, it is "to prepare for risk" for failure as "failure occurs at a certain probability".
In automobiles, for example, it is not acceptable that a part A failure leads a catastrophic failure immediately like uncontrollable engine or steering.
In order to cope with such a failure, it is necessary to prepare for risk by "monitoring abnormality of component A (sign of failure) with component B".
Safety Mechanisms
Safety mechanism is a risk assessment system to ensure functional safety.
Many MCUs are being used in the car for controlling its operation.
When assuming abnormality in the power supply, adding a voltage detector (reset IC) that monitors MCU failure due to overvoltage is a risk preparation, that is, a safety mechanism.
Implementation of safety mechanisms with our power management ICs
Nisshinbo Micro Devices enhance safety and reliability of automobiles by offering products that can be useful for constructing safety mechanisms of customers' systems, such as window type voltage detectors (reset ICs) and system power management ICs with watchdog timer function.
Voltage detector that monitors decrease / rise of output voltage of power supply IC with high accuracy.
R3152 / R1524
With R3152, OV / UV detection accuracy is -1.25% to 0.75%, hysteresis accuracy Max 1.5%, high precision detection is possible. It is a window voltage detector best suited for functional safety requirements to prevent the MCU from operating at abnormal voltage.
Furthermore, a simple system configuration can be realized by combining the voltage regulator R1524 with the maximum input voltage of 36V. The R1524 achieves both low current consumption of 2.2 µA and excellent transient response characteristics, making it ideal for backup system constant voltage source.
System power supply that automatically stops monitoring when the MCU is at sleep mode, or is suspended.
R5114 / R5115
R5114/R5115 is a system power supply integrating an LDO regulator, a voltage detector, and a watchdog timer.
The IC monitors the output current of the LDO regulator while supplying power to the MCU, and at light load, the watchdog timer can automatically stop monitoring clock pulses.
As a result, even if the MCU clock pulse output is stopped during standby, the reset signal is not output from the watchdog timer.
Reset ICs (Voltage Detectors)
| Product Name | VDD | VUVSET | VOVSET | ISS | Features |
|---|---|---|---|---|---|
| R3152 | 3.0 V to 42.0 V | 1.0 V to 4.8 V | 1.1 V to 5.9 V | Typ. 1.5 µA | |
| R3154 | 3.0 V to 42.0 V | 0.55 V to 3.3 V | 0.75 V to 3.7 V | Typ. 2.0 µA | Diagnostic Function |
Watchdog Timer with Reset IC (VD) and LDO Regulator (Linear Regulator)
| Product Name | VIN | VOUT | VDET | ISS | Features |
|---|---|---|---|---|---|
| R5114 | 3.5 V to 42.0 V | 3.3 V to 5.0 V | 2.5 V to 4.8 V | Typ. 8.5 µA | |
| R5115 | 3.5 V to 42.0 V | 3.3 V to 5.0 V | 2.5 V to 4.8 V | Typ. 8.5 µA | Window WDT |
LDO Regulators (Linear Regulators)
| Product Name | VIN | VOUT | ISS | Output Voltage Accuracy |
|---|---|---|---|---|
| R1524 | 3.5 V to 36.0 V | 1.8 V to 9.0 V | Typ. 2.2 µA | ±0.6% (Ta=25°C) |
