Talk:Texas Instruments SN76477

While adding a redirect from SN76477 I discovered that there was a SN76477 article before which had been deleted because of POV, Original research and lack of notibility. I don't know how to find the old article, but hopefully the new one won't suffer from the first two objections. The third is arguable. In my own opinion, sound chips have their own character and are more than generic components. --Malcohol (talk) 15:19, 3 July 2008 (UTC)
 * I think it's notable simply for the fact that this particular chip has its own devoted DIY community following, despite being discontinued. --Theodore Kloba (talk) 14:45, 28 May 2009 (UTC)

Discontinued
The article calls this IC "discontinued until recently" and links to bgmicro.com. Do we know that the product offered by bgmicro is in fact new production? --Theodore Kloba (talk) 14:45, 28 May 2009 (UTC)


 * BGmicro has no website, it does not appear that the chips are available, and i saw one article that indicated they were NOS when they were available. I believe they are still discontinued. 97.113.73.212 (talk) 01:58, 14 April 2023 (UTC)

Possible error in schematics
I believe the redrawn schematics contain an error: according to the chip's specification sheet, "operation is either from a 5v regulated supply applied to Vreg, or from a 7.5v-10v supply applied to the built-in voltage regulator through the Vcc terminal, in which case a regulated 5v is available from the Vreg terminal to power a small amount of external circuitry, or provide a high-logic-level voltage to logic inputs." Until now, I've never seen a schematic that powered BOTH pins simultaneously. While I'm not sure this will cause significant problems, it implies operational requirements that are not correct. --Emerson85 (talk) 20:15, 9 September 2014 (UTC)


 * IMHO the 7805 regulator might be an optional addition. There might have been one or more concerns:


 * the internal regulator might not be able to deliver sufficient current to all the circuitry on the demo board
 * it wouldn't be able to drive the capacitance present on the 5V rail
 * it might overheat the chip


 * Meanwhile, you still want to be able to demonstrate the chip, so you put down all the circuitry and let the engineer using the board remove the parts they don't need.


 * One nice thing about linear regulators is that (often) you can tie their outputs together and still get proper operation, though there is no guarantee of proper current sharing. It's common in isolated switching power supply designs to include a "startup" linear regulator to provide an initial slightly-lower-than-nominal VCC voltage to get the control circuits going until a "bias" winding on the transformer can deliver sufficient power to take over, delivering higher efficiency than the linear regulator. When the linear regulator sees the rail rise higher than its set point, it turns off its pass element. -- 98.156.248.106 (talk) 18:47, 25 May 2019 (UTC)

These redrawn schematics are very unclear
The originals are for better and more understandable. They are available here: http://sandsoftwaresound.net/wp-content/uploads/2021/03/SN76477_schematic.pdf and here: http://sandsoftwaresound.net/sn76477-complex-sound-generator/

I believe if there is no copyright problem they ought to be used instead. 97.113.73.212 (talk) 01:41, 14 April 2023 (UTC)