1 Introduction to HT97230
With the advent of more and more portable audio devices such as smart phones, Bluetooth headsets, wireless microphones, etc., the design space of their boards is becoming less and less; the transmission of audio signals to headphones has always used huge DC blocking capacitors, not only It poses a big challenge to the board space and also has damage to the low-frequency part of the sound quality.
With the general improvement of people's demand for sound quality, the demand for high-fidelity Bluetooth headsets and professional-grade earphone devices is increasing, and gradually extended to ordinary consumers.
Acted by Shenzhen Yongkang Technology Co., Ltd., the HT97230 is a stereo headphone driver chip that does not require DC blocking capacitors. It has an extremely compact BOM and a slim QFN24 lead-free and halogen-free package. In a miniature portable audio device. Its extraordinary distortion, signal-to-noise ratio and completely disappearing click-pop sound, as well as excellent low-frequency fidelity, perfectly adapt to people's increasing sound quality requirements.
Traditional high-fidelity analog headphone amplifiers typically cost a lot of money to maintain low distortion and high fidelity, but still require multiple sound effects from the front of the source to achieve better sound quality. The HT97230 introduces sound adjustment at the headphone amplifier end to meet the different sound quality requirements of customers.
The HT97230 has a 3D surround mode that creates 3D surround sound on stereo headphones, adds impact and surround sound to the headphone sound, and feels surround sound in game rooms and cinemas.
The HT97220 has a bass boost mode that can enhance and enhance the bass of a certain frequency band according to the frequency response characteristics of the earphone to achieve the bass boost effect, and has obvious enhancement effects on the middle bass drum sound and the middle and low volume human voice.
The HT97230 is a headphone driver chip that provides a 3VRMS output drive for a 1kΩ load at 5V supply and a 2VRMS output driver for a 600Ω load at 3.3V supply. At 5V supply, the device provides 125mW for a 32Ω headphone load. The IC provides excellent THD+N over the entire audio band.
The HT97230 internal charge pump inverts the input supply and produces a negative supply. The output stage of the amplifier is powered by the input positive supply and the charge pump output negative supply. The bipolar supply biases the output to zero potential, eliminating the need for large-scale, output-coupled capacitors that are susceptible to distortion.
2 HT97230 advantages and features
・3D surround adjustable
・Bass boost adjustable
・The headphone output does not require a DC blocking capacitor, saving space and cost, and ensuring a complete bass;
・Excellent low frequency fidelity;
・The industry has for the first time eliminated the click-pop sound of the switch SD;
・Extraordinary distortion level, THD+N is as low as 0.001%;
・Excellent noise signal-to-noise ratio, VN: 7uV, SNR: 112dB;
・Supports fully differential input and single-ended input;
・Output capability: 125mW (fIN = 1kHz, VDD=5V, RL=32Ω, THD+N=1%);
3Vrms (fIN = 1kHz, VDD=5V, RL=1kΩ, THD+N<0.1%);
2Vrms (fIN = 1kHz, VDD=5V, RL=600Ω, THD+N<0.1%);
・ Extremely streamlined, lead-free and halogen-free QFN24L-PP package;
・Power supply: 2.5 - 5.5V.
3 HT97230 application
Bluetooth earphone.
Blu-ray, DVD player.
Professional audio equipment.
Set-top box.
4 HT97230 Application Design Highlights
A. Mode control
Through the control of pin17 CTL, the HT97230 can enter different working modes. This pin supports two control modes:
(1) Voltage control method
Entering a certain voltage on the CTL pin allows the HT97230 to enter different operating modes, as shown in the following table:
(2) One-line pulse mode
But CTRL is pulled high to PVDD (as in Table 1 above). Enter different pulse numbers on the CTRL pin to enter different working modes, as shown in the following table:
B. Normal Mode
Gain setting:
AV0 = RF/RIN, (RF = RF3//(RF1+RF2))
C. Bass Mode
Bass boost +3dB frequency point
D. 3D Mode
3D surround sound function starts +3dB frequency point
E. Input filter
The input capacitor CIN and the input resistor RIN form a high-pass filter whose cutoff frequency affects the input of the low frequency signal. Cut-off frequency:
f-3dB = 1/(2Ï€RINCIN)
F. Input capacitor CIN, input resistor RIN, feedback resistor RF
The input capacitor CIN, the input resistor RIN, and the feedback resistor RF should use high-precision devices as much as possible to enable the chip to perform better distortion, signal-to-noise ratio and other performance.
5 HT97230 application diagram
Fig.1 Top View of HT97230
Fig.2 Typical Application of HT97230
Fig. 3 Schematic Diagram of HT97230 Demo Board
Fig.4 Top View of HT97230 Demo Board PCB Layout
Fig.5 Bottom View of HT97230 Demo Board PCB Layout
Solar Generator,Wind Power Generator,Home Generators,Solar Generator
Shaoxing AnFu Energy Equipment Co.Ltd , https://www.sxanfu.com