https://www.righto.com/2020/07/inside-8086-processor-tiny-charge-pumps.html
Introduced in 1978, the revolutionary Intel 8086 microprocessor led to the x86 processors used in most desktop and server computing today. This chip is built from digital circuits, as you would expect. However, it also has analog circuits: charge pumps that turn the 8086's 5-volt supply into a negative voltage to improve performance.1 I've been reverse-engineering the 8086 from die photos, and in this post I discuss the construction of these charge pumps and how they work.
[...] An integrated circuit starts with a silicon substrate, and transistors are built on this. For high-performance integrated circuits, it is beneficial to apply a negative "bias" voltage to the substrate. 2 To obtain this substrate bias voltage, many chips in the 1970s had an external pin that was connected to -5V,3 but this additional power supply was inconvenient for the engineers using these chips. By the end of the 1970s, however, on-chip "charge pump" circuits were designed that generated the negative voltage internally. These chips used a single convenient +5V supply, making engineers happier.
(Score: 4, Funny) by Rosco P. Coltrane on Sunday May 14, @02:27AM (1 child)
Yeah that's great. But all they had to do was daisy-chain another charge pump to the first one to generate +5V internally from the -5V and the chip wouldn't have needed a power supply at all.
Laxy chip designers man...
(Score: 2) by turgid on Sunday May 14, @10:53AM
This could be scaled up and solve the energy crisis. I'd like to invest in your scheme. I have $2.49.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].