NCV33035 データシートの表示（PDF） - ON Semiconductor

部品番号

コンポーネント説明

メーカー

NCV33035

Brushless DC Motor Controller

ON Semiconductor 

MC33035, NCV33035

Capacitor CT

Error Amp

Out/PWM

Input

Current

Sense Input

Latch Set"

Inputs

Top Drive

Outputs

Bottom Drive

Outputs

Fault Output

Figure 21. Pulse Width Modulator Timing Diagram

Reference

The on−chip 6.25 V regulator (Pin 8) provides charging

current for the oscillator timing capacitor, a reference for the

error amplifier, and can supply 20 mA of current suitable for

directly powering sensors in low voltage applications. In

higher voltage applications, it may become necessary to

transfer the power dissipated by the regulator off the IC. This

is easily accomplished with the addition of an external pass

transistor as shown in Figure 22. A 6.25 V reference level

was chosen to allow implementation of the simpler NPN

circuit, where Vref − VBE exceeds the minimum voltage

required by Hall Effect sensors over temperature. With

proper transistor selection and adequate heatsinking, up to

one amp of load current can be obtained.

17

Vin

UVLO

18

REF

MPS

8

U01A

To

Sensor

Power

≈5.6 V

Control

Circuitry

6.25 V

Vin

39

17

UVLO

18

MPS

U51A

REF

0.1 8

To Control Circuitry

and Sensor Power

6.25 V

The NPN circuit is recommended for powering Hall or opto sensors, where

the output voltage temperature coefficient is not critical. The PNP circuit is

slightly more complex, but is also more accurate over temperature. Neither

circuit has current limiting.

Figure 22. Reference Output Buffers

Undervoltage Lockout

A triple Undervoltage Lockout has been incorporated to

prevent damage to the IC and the external power switch

transistors. Under low power supply conditions, it

guarantees that the IC and sensors are fully functional, and

that there is sufficient bottom drive output voltage. The

positive power supplies to the IC (VCC) and the bottom

drives (VC) are each monitored by separate comparators that

have their thresholds at 9.1 V. This level ensures sufficient

gate drive necessary to attain low RDS(on) when driving

standard power MOSFET devices. When directly powering

the Hall sensors from the reference, improper sensor

operation can result if the reference output voltage falls

below 4.5 V. A third comparator is used to detect this

condition. If one or more of the comparators detects an

undervoltage condition, the Fault Output is activated, the top

drives are turned off and the bottom drive outputs are held

in a low state. Each of the comparators contain hysteresis to

prevent oscillations when crossing their respective

thresholds.

Fault Output

The open collector Fault Output (Pin 14) was designed to

provide diagnostic information in the event of a system

malfunction. It has a sink current capability of 16 mA and

can directly drive a light emitting diode for visual indication.

Additionally, it is easily interfaced with TTL/CMOS logic

for use in a microprocessor controlled system. The Fault

Output is active low when one or more of the following

conditions occur:

1) Invalid Sensor Input code

2) Output Enable at logic [0]

3) Current Sense Input greater than 100 mV

4) Undervoltage Lockout, activation of one or more of

the comparators

5) Thermal Shutdown, maximum junction temperature

being exceeded

This unique output can also be used to distinguish between

motor start−up or sustained operation in an overloaded

condition. With the addition of an RC network between the

Fault Output and the enable input, it is possible to create a

time−delayed latched shutdown for overcurrent. The added

circuitry shown in Figure 23 makes easy starting of motor

systems which have high inertial loads by providing

additional starting torque, while still preserving overcurrent

protection. This task is accomplished by setting the current

limit to a higher than nominal value for a predetermined time.

During an excessively long overcurrent condition, capacitor

CDLY will charge, causing the enable input to cross its

threshold to a low state. A latch is then formed by the positive

feedback loop from the Fault Output to the Output Enable.

Once set, by the Current Sense Input, it can only be reset by

shorting CDLY or cycling the power supplies.

http://onsemi.com

12

Share Link: