 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
QT1+T+G Datasheet(PDF) 5 Page - Quantum Research Group |
|
||||||||||||||||||||||||||||||
QT1+T+G Datasheet(HTML) 5 Page - Quantum Research Group |
|
|
5 / 14 page  that increments with each detection until a limit is reached, after which the output is activated. If no detection is sensed prior to the final count, the counter is reset immediately to zero. The required count is 4. The Detection Integrator can also be viewed as a 'consensus' filter, that requires four detections in four successive bursts to create an output. As the basic burst spacing is 95ms, if this spacing was maintained through 4 consecutive bursts the sensor would be very slow to respond. In the QT118H, after an initial detection is sensed, the remaining three bursts are spaced only about 2ms apart, so that the slowest reaction time possible is the fastest possible. 2.1.5 FORCED SENSOR RECALIBRATION The QT118H has no recalibration pin; a forced recalibration is accomplished only when the device is powered up. However, the supply drain is so low it is a simple matter to treat the entire IC as a controllable load; simply driving the QT118H's Vdd pin directly from another logic gate or a microprocessor port (Figure 2-2) will serve as both power and 'forced recal'. The source resistance of most CMOS gates and microprocessors is low enough to provide direct power without any problems. Almost any CMOS logic gate can directly power the QT118H. A 0.01uF minimum bypass capacitor close to the device is essential; without it the device can break into high frequency oscillation. Option strap configurations are read by the QT118H only on powerup. Configurations can only be changed by powering the QT118H down and back up again; a microcontroller can directly alter most of the configurations and cycle power to put them in effect. 2.2 OUTPUT FEATURES The QT118H is designed for maximum flexibility and can accommodate most popular sensing requirements. These are selectable using strap options on pins OPT1 and OPT2. All options are shown in Table 2-1. OPT1 and OPT2 should never be left floating. If they are floated, the device will draw excess power and the options will not be properly read on powerup. Intentionally, there are no pullup resistors on these lines, since pullup resistors add to power drain if the pin(s) are tied low. 2.2.1 DC MODE OUTPUT The output of the device can respond in a ‘DC mode’, where the output is active-high upon detection. The output will remain active for the duration of the detection, or until the Max On-Duration expires, whichever occurs first. If the latter occurs first, the sensor performs a full recalibration and the output becomes inactive until the next detection. In this mode, two nominal Max On-Duration timeouts are available: 10 and 60 seconds. 2.2.2 TOGGLE MODE OUTPUT This makes the sensor respond in an on/off mode like a flip flop. It is most useful for controlling power loads, for example in kitchen appliances, power tools, light switches, etc. Max On-Duration in Toggle mode is fixed at 10 seconds. When a timeout occurs, the sensor recalibrates but leaves the output state unchanged. 10s Vdd Gnd Pulse 10s Gnd Gnd Toggle 60s Gnd Vdd DC Out 10s Vdd Vdd DC Out Max On- Duration Tie Pin 4 to: Tie Pin 3 to: Table 2-1 Output Mode Strap Options 2.2.3 PULSE MODE OUTPUT This generates a positive pulse of 95ms duration with every new detection. It is most useful for 2-wire operation (see Figure 1-2), but can also be used when bussing together several devices onto a common output line with the help of steering diodes or logic gates, in order to control a common load from several places. Max On-Duration is fixed at 10 seconds if in Pulse output mode. The piezo beeper drive does not operate in Pulse mode. 2.2.4 HEARTBEAT™ OUTPUT The output has a full-time HeartBeat™ ‘health’ indicator superimposed on it. This operates by taking 'Out' into a tri-state mode for 350µs once before every QT burst. This output state can be used to determine that the sensor is operating properly, or, it can be ignored using one of several simple methods. Since Out is normally low, a pullup resistor will create positive HeartBeat pulses (Figure 2-3) when the sensor is not detecting an object; when detecting an object, the output will remain active for the duration of the detection, and no HeartBeat pulse will be evident. If the sensor is wired to a microcontroller as shown in Figure 2-4, the controller can reconfigure the load resistor to either ground or Vcc depending on the output state of the device, so that the pulses are evident in either state. Electromechanical devices will usually ignore this short pulse. The pulse also has too low a duty cycle to visibly activate LED’s. It can be filtered completely if desired, by adding an RC timeconstant to filter the output, or if interfacing directly and only to a high-impedance CMOS input, by doing nothing or at most adding a small non-critical capacitor from Out to ground (Figure 2-5). lq 5 QT118H R1.08 / 0405 Figure 2-2 Powering From a CMOS Port Pin 0.01µ F C M O S m ic rocon troller OUT P ORT X. m P ORT X. n Vdd Vss QT11 8 |
Similar Part No. - QT1+T+G |
|
Similar Description - QT1+T+G |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
allmanual.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
