LM5112SD/NOPB vs LM5109ASD/NOPB
| Part Number |
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| Category | PMIC - Gate Drivers | PMIC - Gate Drivers |
| Manufacturer | Texas Instruments | Texas Instruments |
| Description | IC GATE DRVR LOW-SIDE 6WSON | IC GATE DRVR HALF-BRIDGE 8WSON |
| Package | -Reel® | Cut Tape (CT) |
| Series | - | - |
| Voltage - Supply | 3.5V ~ 14V | 8V ~ 14V |
| Operating Temperature | -40°C ~ 125°C (TJ) | -40°C ~ 125°C (TJ) |
| Mounting Type | Surface Mount | Surface Mount |
| Package / Case | 6-WDFN Exposed Pad | 8-WDFN Exposed Pad |
| Supplier Device Package | 6-WSON (3x3) | 8-WSON (4x4) |
| Input Type | Inverting, Non-Inverting | Non-Inverting |
| Channel Type | Single | Independent |
| Rise / Fall Time (Typ) | 14ns, 12ns | 15ns, 15ns |
| Driven Configuration | Low-Side | Half-Bridge |
| Number of Drivers | 1 | 2 |
| Gate Type | N-Channel MOSFET | N-Channel MOSFET |
| Logic Voltage - VIL, VIH | 0.8V, 2.3V | 0.8V, 2.2V |
| Current - Peak Output (Source, Sink) | 3A, 7A | 1A, 1A |
| High Side Voltage - Max (Bootstrap) | - | 108 V |
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1. What is a gate driver?
Circuit, gate signal enhancement, controller
A gate driver is a circuit that is mainly used to enhance the gate signal of a field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) so that the controller can better control the operation of these semiconductor switches ，The gate driver controls the gate of the MOSFET or IGBT by converting the signal output by the controller into a high-voltage, high-current pulse, thereby improving the performance, reliability and service life of these devices.
Working principle
The gate driver is mainly composed of an input stage, a driver stage and an output stage:
Input stage: responsible for receiving the signal output by the controller and converting it into a TTL or CMOS logic level.
Driver stage: amplifies and converts the signal to generate a high-voltage, high-current pulse signal.
Output stage: uses these pulse signals to control the gate of the MOSFET or IGBT. -
2. How to choose a gate driver for a MOSFET?
When selecting a gate driver for a MOSFET, the following key factors need to be considered:
Current drive capability: The current drive capability of the gate driver directly affects the turn-on and turn-off speed of the MOSFET. Higher current sinking and sourcing capabilities mean faster turn-on and turn-off speeds, thereby reducing switching losses.
Fault detection function: The gate driver should have fault detection functions such as undervoltage lockout (UVLO), desaturation (DESAT) detection, etc. to ensure the safety and stable operation of the system.
Interference immunity: Common mode transient immunity (CMTI) is an important parameter to measure the anti-interference ability of the gate driver. In high-power systems, high CMTI values can better resist voltage transients and ensure stable operation of the system.
Electrical isolation: Electrically isolated gate drivers can achieve electrical isolation between control signals and power devices to ensure system safety. Optical coupling isolation and magnetic coupling isolation are common electrical isolation technologies, and the selection should be compared according to application requirements.
Switching frequency: For high-frequency switching applications, the switching frequency of the gate driver should match the switching frequency of the MOSFET to ensure efficient operation.
Transmission delay: Transmission delay and transmission delay matching are important parameters of electrical isolation drivers, which affect the response speed of the signal and the stability of the system. -
3. What is an active gate driver?
An active gate driver is a circuit that is mainly used to enhance the gate signal of a field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) so that the controller can better control the operation of these semiconductor switches. It controls the gate of MOSFET or IGBT by converting the signal output by the controller into high-voltage, high-current pulses, thereby improving the performance, reliability and service life of these devices.
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4. Why is a gate driver needed?
The main reasons for the need for gate drivers include signal amplification, electrical isolation, and protection mechanisms.
Signal Amplification
The main function of the gate driver is to convert the low-voltage signal of the controller into a high-voltage drive signal, thereby achieving effective control of the power device. This signal amplification function ensures that the power device can be stably turned on and off, improving the efficiency and reliability of the system.
Electrical Isolation
In many applications, electrical isolation between the control circuit and the power semiconductor is very important to prevent voltage feedback or ground loop problems. Gate drivers usually use optocouplers or other isolation methods to maintain this isolation, ensuring that the control circuit is not affected by the power circuit, thereby improving the stability and safety of the system.
Protection Mechanism
Gate drivers also integrate a variety of protection functions, such as overcurrent, overvoltage protection, and short-circuit protection. These protection mechanisms can effectively prevent power device damage and improve the reliability and safety of the system.
