Overview
The NCV8878, specifically the NCV887801D1R2G model, is an automotive-grade non-synchronous boost controller designed by onsemi. This controller is engineered to maintain a minimum output voltage during Start-Stop vehicle operations when the battery voltage sags. It drives an external N-channel MOSFET and utilizes peak current mode control with internal slope compensation to ensure stable operation. The device features an internal regulator for the gate driver and incorporates various protection mechanisms such as cycle-by-cycle current limiting, thermal shutdown, and low quiescent current sleep mode operation.
Key Specifications
| Characteristic | Symbol | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Quiescent Current, Sleep Mode | Iq,sleep | VOUT = 13.2 V, TJ = 25°C, DISB = 0 V | − | 12 | 14 | μA |
| Quiescent Current, No switching | Iq,off | Into VOUT pin, VOUT,reg < VOUT < VOUT,des, No switching | − | 2.2 | 4.0 | mA |
| Switching Frequency | FSW | NCV887801 | 405 | 450 | 495 | kHz |
| Minimum Pulse Width | ton,min | NCV887801 | 90 | 115 | 145 | ns |
| Maximum Duty Cycle | Dmax | NCV887801 | 81 | 83 | 85 | % |
| Slope Compensating Ramp | Sa | NCV887801 | 46 | 53 | 60 | mV/μs |
| Current Limit Threshold Voltage | Vcl | NCV887801 | − | 200 | − | mV |
| Gate Drive Sourcing Current | Isrc | NCV887801 | − | 800 | − | mA |
| Gate Drive Sinking Current | Isink | NCV887801 | − | 600 | − | mA |
| Output Voltage Regulation | VOUT | NCV887801 | − | 6.8 | − | V |
Key Features
- Automatic Enable Below Wake Up Threshold Voltage: The device is enabled when the supply voltage drops below the wake-up threshold, which is factory programmable.
- Status Pin Diagnostic Function: An open-drain diagnostic output indicates the IC's status and operation.
- Override Disable Function: The device can be disabled via the DISB input.
- Boost Mode Operation at Regulation Set Point: Boost operation is initiated when the supply voltage drops below the regulation set point.
- Peak Current Mode Control with Internal Slope Compensation: Ensures stable operation and prevents sub-harmonic oscillations.
- Low Quiescent Current Sleep Mode Operation: Reduces power consumption when not in active boost mode).
- Current Limit Protections: Includes cycle-by-cycle current limiting and overcurrent hiccup mode protection).
- Thermal Shutdown: Protects the device from overheating).
- Undervoltage Lockout (UVLO): Ensures the device operates only when the input voltage is sufficient to support internal rails and power the controller).
Applications
The NCV8878, particularly the NCV887801D1R2G, is designed for automotive applications, especially in Start-Stop systems where maintaining a stable output voltage during battery voltage sags is crucial. It is also suitable for other applications requiring robust and efficient boost conversion, such as industrial power supplies, battery-powered systems, and any scenario where a reliable and efficient boost controller is needed).
Q & A
- What is the primary function of the NCV8878?
The NCV8878 is a non-synchronous boost controller designed to maintain a minimum output voltage during Start-Stop vehicle operations when the battery voltage sags).
- How does the NCV8878 control the output voltage?
The device uses peak current mode control with internal slope compensation to ensure stable operation and prevent sub-harmonic oscillations).
- What are the key protection features of the NCV8878?
The device includes cycle-by-cycle current limiting, thermal shutdown, and overcurrent hiccup mode protection).
- How does the NCV8878 handle low input voltage conditions?
The device features an undervoltage lockout (UVLO) to ensure it operates only when the input voltage is sufficient to support internal rails and power the controller).
- What is the typical switching frequency of the NCV887801D1R2G?
The typical switching frequency is 450 kHz).
- How does the device manage quiescent current in sleep mode?
The NCV8878 has a low quiescent current sleep mode to reduce power consumption when not in active boost mode).
- What is the purpose of the status pin on the NCV8878?
The status pin provides a diagnostic output indicating the IC's status and operation).
- Can the NCV8878 be disabled externally?
Yes, the device can be disabled via the DISB input).
- What is the output voltage regulation accuracy of the NCV8878?
The output voltage regulation accuracy is ±2% over the temperature range).
- Is the NCV8878 suitable for automotive applications?
Yes, the NCV8878 is AEC-Q100 qualified and designed for automotive and other applications requiring unique site and control change requirements).
