HT62104 Infrared Remote Encoder IC

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Steven Bruce
5 years ago
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1 D/A:AN0304E Introduction The HT6204 is a high performance infrared remote encoder capable of encoding a signal with a 3-bit start code, 2-bit custom code and 7-bit data code. The HT6204 device has 8 key inputs. When one of the keys is triggered, the programmed code is generated and transmitted via an IR (38kHz carrier) transmission medium. Features Operating voltage : 2.0V ~ 5.0V Eight data key control Two custom codes for product differentiation Start oscillation after a key press to save power LED output to indicate transmission status Direct 38kHz output frequency infrared LED modulation Signal gap time : T= 4 92 (/455kHz) 4 6 (/38kHz) HT6204 signal gap time : 4T Low power consumption Package Type : 6-pin DIP/NSOP Applications Household appliance control: electric fans, air cleaners, lamp remote control Toy remote control Rolling door remote control Consumer product remote control

2 Encoder Function Description When any of the K~K8 keys is activated, a transmission code, comprised of a 3-bit start code, a 2-bit custom code and a 7-bit data code (as defined by the K~K8 status) is output on the DOUT pin. If the key remains held down, the transmission code will be continuously transmitted. The following diagram shows the signal content : A single frame data format is shown below. The following shows a complete code word transmission signal. Note : The time duration between Frame (n) and Frame (n+) is called the Signal Gap Time. The Gap Time is calculated based on a unit period, denoted as T. T kHz 38kHz K~K8 corresponds to a 7-bit data code table: Ke Start Code y Custom Data Code Code S2 S S0 C C2 D6 D5 D4 D3 D2 D D0 K 0 C C K2 0 C C K3 0 C C K4 0 C C K5 0 C C K6 0 C C K7 0 C C K8 0 C C The C and C2 pins are internally connected to pull-high resistors whose status is decided by customers. A connection to GND represents a 0 while a connection to VDD or a floating state represents a. 2

3 Carrier Output Waveform The carrier signal, with a frequency of 38kHz, is superimposed onto the output data signal which is used to generate the data 0 and data waveforms. The carrier signal is shown in the following diagram. Bit Code Waveform of DOUT Pin As bits can be designated as either 0 or, they must be encoded in a certain way as shown below. Note: kHz 6 38kHz 2. Bit consists of a high pulse for and a 38kHz carrier for Bit 0 consists of a high pulse for 3 and a 38kHz carrier for. 4. The time unit t DW is specified as follows: Symb Test Condition Parameter Min. Typ. Max. Unit ol V DD Condition Ta=25 C, Load =k for ms DOUT pin (-.5%) (+.5%) t DW Single Data Bit Width 2.2V~ 3.6V 0 C < 25 C < 50 C ms Load =k for DOUT pin (-2.3%) (+2.3%) The influence of the Data bit time (t DW ) tolerance to the transmission distance information is provided for reference only. Conditons: Ta=25 C, V DD =3V, IR LED =YiGuang IR7393. Refer to Fig. for the test circuit. t DW (ms) t DW Transmission Tolerance Distance Note.688 0% 9.2m There is a relationship between the.67 ~.7049 ±% 9.2m transmission distance and the IR LED.6542~.728 ±2% 8.3m transmission power..6458~.7302 ±2.5% 6.5m.6374~.7386 ±3% 5.0m 3

4 Operation Flowchart Application Circuit Fig.: It is recommended to use the following circuit where the VDD pin does not have an RC filter circuit: Note:. A µf ceramic capacitor should be connected to the VDD pin and located as close to the device as possible. 2. It is necessary to use 330µF value capacitor for C. Other values may influence the frequency stability and lower the transmission distance. 3. The HT6204 application circuit does not require a drive transistor or a 455kHz resonator but the xx504 application circuit still requires these components. This results in fewer external components for HT6204 applications with resulting lower costs. 4. Users do not need to change the receiver end application program. 4

2:It is recommended the following circuit is used where the VDD pin has an additional RC filter circuit. Here the frequency stability is higher than that of Fig.. V DD Note:.

5 IR LED IR333C-A(Q) LED 5. If users do not want to modify their PCB Layout, the following Fig. application circuit shows how to change certain components on the board to achieve the same function. Fig.2:It is recommended the following circuit is used where the VDD pin has an additional RC filter circuit. Here the frequency stability is higher than that of Fig.. V DD Note:. R2 and C2 should be located as close to the VDD Pin as possible 2. If V BAT 3.6V, C= 00µF is recommended. If V BAT >3.6V, C=220µF is recommended, as it achieves higher frequency stability and longer transmission distances than with a 00µF capacitor. 3. VSS, VSS and VSS2 should be connected to GND. 4. VDD and VDD should be connected to VDD.. 5

3 12 Series of Encoders

3 12 Series of Encoders Features Operating voltage: 2.4V~12V Low power and high noise immunity CMOS technology Low standby current Minimum transmission word: Four words for TE trigger One word for Data trigger Applications Burglar