February 21, 2000
Development of a power IC (SI-5300) for driving DC motors used for throttle valve control in automobile engines
Sanken Electric Co. Ltd., has recently developed the SI-5300 power IC (size: 35mm ´ 4.8mm ´ 24.8mm) for driving DC motors used for throttle valve control in automotive engines.The SI-5300 is a single package integrating low on-resistance (about 1/2 the conventional value per silicon area) P-channel and N-channel MOSFETs developed for electronically controlled throttle valves (two each) with a bridge configuration based on a monolithic IC for control. The package achieves the high current required for starting the DC motors used for throttle valve control (DC 5A, with pulse-based 17 A output current and low loss). It also helps to reduce the number of parts and the size of boards in the engine control unit (ECU) installed in the vehicle, thus satisfying the requirements for greater ECU compactness, lower ECU cost, and allowing the ECU to be built in to the motor.
We started shipping samples at the end of February, and will start mass-production at the Ishikawa Sanken Shika Plant in April of this year. Currently, we are focusing on the domestic market (Year 2001 model), with planned sales of 40,000 units/month this year, and 200,000 units/month starting next year. The sample price is ¥1500.
[Development background]
In recent years, more and more vehicles have featured lean-burning, direct injection engines in order to help reduce environmental pollution. In order to help reduce exhaust emissions and lower fuel consumption, throttle valves using DC motors have been converted to electronic control. This conversion to electronics technology is essential to support Drive By Wire (DBW) for ITS automated driving control.
In order to control the rotation of DC motors used for precisely controlling throttle valves, a technology for logically controlling four power transistors in the drive circuit is required. Furthermore - in terms of the load characteristics of these power elements - a current capacity of several amps is required constantly, with a capacity of more than 10 amps is required at motor start-up time.
However, integrating these high-capacity power elements into a single chip is difficult using current technology, as at least five power semiconductors are needed.At Sanken Electric, we are developing control ICs and low on-resistance MOSFETs to solve this problem. The SI-5300 offers greater ECU compactness and lower price by integrating three technologies developed over many years within our original SPM package (15-pin): (1) Hybridization technology using mold packages; (2) Technologies and the corresponding expertise for combining control ICs with suitable power elements; and (3) Sophisticated bonding technology.
[Development Features]
| (1) | Employing P-channel MOSFET for high-side power MOSFET When an N-channel MOSFET is used for the high-side, a circuit is necessary. However, no charge pump circuit is needed when using a P-channel MOSFET. This eliminates generation of switching noise by the charge pump circuit, and prevents radio interference. |
| (2) | Controlling four power MOSFETs using a single control IC In our system, four power MOSFETs are driven using a single control IC, allowing the power IC to incorporate various protection functions such as a simultaneous ON prevention circuit for power MOSFET, an overcurrent protection circuit with DIAG signal output, and an overheating protection circuit. |
| (3) | Employing power MOSFET with current sensing The control IC detects sensing current branched from the power MOSFET, allowing it to protect each power MOSFET from overcurrent in the range of 20A or more without the need for large, high-capacity detection resistance circuits. This results in low loss and greater compactness. |
